mono/metadata/threadpool-ms.c

   1 /*
   2  * threadpool-ms.c: Microsoft threadpool runtime support
   3  *
   4  * Author:
   5  *      Ludovic Henry (ludovic.henry@xamarin.com)
   6  *
   7  * Copyright 2015 Xamarin, Inc (http://www.xamarin.com)
   8  * Licensed under the MIT license. See LICENSE file in the project root for full license information.
   9  */
  10
  11 //
  12 // Copyright (c) Microsoft. All rights reserved.
  13 // Licensed under the MIT license. See LICENSE file in the project root for full license information.
  14 //
  15 // Files:
  16 //  - src/vm/comthreadpool.cpp
  17 //  - src/vm/win32threadpoolcpp
  18 //  - src/vm/threadpoolrequest.cpp
  19 //  - src/vm/hillclimbing.cpp
  20 //
  21 // Ported from C++ to C and adjusted to Mono runtime
  22
  23 #include <stdlib.h>
  24 #define _USE_MATH_DEFINES // needed by MSVC to define math constants
  25 #include <math.h>
  26 #include <config.h>
  27 #include <glib.h>
  28
  29 #include <mono/metadata/class-internals.h>
  30 #include <mono/metadata/exception.h>
  31 #include <mono/metadata/gc-internals.h>
  32 #include <mono/metadata/object.h>
  33 #include <mono/metadata/object-internals.h>
  34 #include <mono/metadata/threadpool-ms.h>
  35 #include <mono/metadata/threadpool-ms-io.h>
  36 #include <mono/metadata/w32event.h>
  37 #include <mono/utils/atomic.h>
  38 #include <mono/utils/mono-compiler.h>
  39 #include <mono/utils/mono-complex.h>
  40 #include <mono/utils/mono-lazy-init.h>
  41 #include <mono/utils/mono-logger.h>
  42 #include <mono/utils/mono-logger-internals.h>
  43 #include <mono/utils/mono-proclib.h>
  44 #include <mono/utils/mono-threads.h>
  45 #include <mono/utils/mono-time.h>
  46 #include <mono/utils/mono-rand.h>
  47
  48 #define CPU_USAGE_LOW 80
  49 #define CPU_USAGE_HIGH 95
  50
  51 #define MONITOR_INTERVAL 500 // ms
  52 #define MONITOR_MINIMAL_LIFETIME 60 * 1000 // ms
  53
  54 #define WORKER_CREATION_MAX_PER_SEC 10
  55
  56 /* The exponent to apply to the gain. 1.0 means to use linear gain,
  57  * higher values will enhance large moves and damp small ones.
  58  * default: 2.0 */
  59 #define HILL_CLIMBING_GAIN_EXPONENT 2.0
  60
  61 /* The 'cost' of a thread. 0 means drive for increased throughput regardless
  62  * of thread count, higher values bias more against higher thread counts.
  63  * default: 0.15 */
  64 #define HILL_CLIMBING_BIAS 0.15
  65
  66 #define HILL_CLIMBING_WAVE_PERIOD 4
  67 #define HILL_CLIMBING_MAX_WAVE_MAGNITUDE 20
  68 #define HILL_CLIMBING_WAVE_MAGNITUDE_MULTIPLIER 1.0
  69 #define HILL_CLIMBING_WAVE_HISTORY_SIZE 8
  70 #define HILL_CLIMBING_TARGET_SIGNAL_TO_NOISE_RATIO 3.0
  71 #define HILL_CLIMBING_MAX_CHANGE_PER_SECOND 4
  72 #define HILL_CLIMBING_MAX_CHANGE_PER_SAMPLE 20
  73 #define HILL_CLIMBING_SAMPLE_INTERVAL_LOW 10
  74 #define HILL_CLIMBING_SAMPLE_INTERVAL_HIGH 200
  75 #define HILL_CLIMBING_ERROR_SMOOTHING_FACTOR 0.01
  76 #define HILL_CLIMBING_MAX_SAMPLE_ERROR_PERCENT 0.15
  77
  78 typedef union {
  79         struct {
  80                 gint16 max_working; /* determined by heuristic */
  81                 gint16 active; /* executing worker_thread */
  82                 gint16 working; /* actively executing worker_thread, not parked */
  83                 gint16 parked; /* parked */
  84         } _;
  85         gint64 as_gint64;
  86 } ThreadPoolCounter;
  87
  88 typedef struct {
  89         MonoDomain *domain;
  90         /* Number of outstanding jobs */
  91         gint32 outstanding_request;
  92         /* Number of currently executing jobs */
  93         int     threadpool_jobs;
  94         /* Signalled when threadpool_jobs + outstanding_request is 0 */
  95         /* Protected by threadpool->domains_lock */
  96         MonoCoopCond cleanup_cond;
  97 } ThreadPoolDomain;
  98
  99 typedef MonoInternalThread ThreadPoolWorkingThread;
 100
 101 typedef struct {
 102         gint32 wave_period;
 103         gint32 samples_to_measure;
 104         gdouble target_throughput_ratio;
 105         gdouble target_signal_to_noise_ratio;
 106         gdouble max_change_per_second;
 107         gdouble max_change_per_sample;
 108         gint32 max_thread_wave_magnitude;
 109         gint32 sample_interval_low;
 110         gdouble thread_magnitude_multiplier;
 111         gint32 sample_interval_high;
 112         gdouble throughput_error_smoothing_factor;
 113         gdouble gain_exponent;
 114         gdouble max_sample_error;
 115
 116         gdouble current_control_setting;
 117         gint64 total_samples;
 118         gint16 last_thread_count;
 119         gdouble elapsed_since_last_change;
 120         gdouble completions_since_last_change;
 121
 122         gdouble average_throughput_noise;
 123
 124         gdouble *samples;
 125         gdouble *thread_counts;
 126
 127         guint32 current_sample_interval;
 128         gpointer random_interval_generator;
 129
 130         gint32 accumulated_completion_count;
 131         gdouble accumulated_sample_duration;
 132 } ThreadPoolHillClimbing;
 133
 134 typedef struct {
 135         ThreadPoolCounter counters;
 136
 137         GPtrArray *domains; // ThreadPoolDomain* []
 138         MonoCoopMutex domains_lock;
 139
 140         GPtrArray *working_threads; // ThreadPoolWorkingThread* []
 141         gint32 parked_threads_count;
 142         MonoCoopCond parked_threads_cond;
 143         MonoCoopMutex active_threads_lock; /* protect access to working_threads and parked_threads */
 144
 145         guint32 worker_creation_current_second;
 146         guint32 worker_creation_current_count;
 147         MonoCoopMutex worker_creation_lock;
 148
 149         gint32 heuristic_completions;
 150         gint64 heuristic_sample_start;
 151         gint64 heuristic_last_dequeue; // ms
 152         gint64 heuristic_last_adjustment; // ms
 153         gint64 heuristic_adjustment_interval; // ms
 154         ThreadPoolHillClimbing heuristic_hill_climbing;
 155         MonoCoopMutex heuristic_lock;
 156
 157         gint32 limit_worker_min;
 158         gint32 limit_worker_max;
 159         gint32 limit_io_min;
 160         gint32 limit_io_max;
 161
 162         MonoCpuUsageState *cpu_usage_state;
 163         gint32 cpu_usage;
 164
 165         /* suspended by the debugger */
 166         gboolean suspended;
 167 } ThreadPool;
 168
 169 typedef enum {
 170         TRANSITION_WARMUP,
 171         TRANSITION_INITIALIZING,
 172         TRANSITION_RANDOM_MOVE,
 173         TRANSITION_CLIMBING_MOVE,
 174         TRANSITION_CHANGE_POINT,
 175         TRANSITION_STABILIZING,
 176         TRANSITION_STARVATION,
 177         TRANSITION_THREAD_TIMED_OUT,
 178         TRANSITION_UNDEFINED,
 179 } ThreadPoolHeuristicStateTransition;
 180
 181 static mono_lazy_init_t status = MONO_LAZY_INIT_STATUS_NOT_INITIALIZED;
 182
 183 enum {
 184         MONITOR_STATUS_REQUESTED,
 185         MONITOR_STATUS_WAITING_FOR_REQUEST,
 186         MONITOR_STATUS_NOT_RUNNING,
 187 };
 188
 189 static gint32 monitor_status = MONITOR_STATUS_NOT_RUNNING;
 190
 191 static ThreadPool* threadpool;
 192
 193 #define COUNTER_CHECK(counter) \
 194         do { \
 195                 g_assert (counter._.max_working > 0); \
 196                 g_assert (counter._.working >= 0); \
 197                 g_assert (counter._.active >= 0); \
 198         } while (0)
 199
 200 #define COUNTER_READ() (InterlockedRead64 (&threadpool->counters.as_gint64))
 201
 202 #define COUNTER_ATOMIC(var,block) \
 203         do { \
 204                 ThreadPoolCounter __old; \
 205                 do { \
 206                         g_assert (threadpool); \
 207                         __old.as_gint64 = COUNTER_READ (); \
 208                         (var) = __old; \
 209                         { block; } \
 210                         COUNTER_CHECK (var); \
 211                 } while (InterlockedCompareExchange64 (&threadpool->counters.as_gint64, (var).as_gint64, __old.as_gint64) != __old.as_gint64); \
 212         } while (0)
 213
 214 #define COUNTER_TRY_ATOMIC(res,var,block) \
 215         do { \
 216                 ThreadPoolCounter __old; \
 217                 do { \
 218                         g_assert (threadpool); \
 219                         __old.as_gint64 = COUNTER_READ (); \
 220                         (var) = __old; \
 221                         (res) = FALSE; \
 222                         { block; } \
 223                         COUNTER_CHECK (var); \
 224                         (res) = InterlockedCompareExchange64 (&threadpool->counters.as_gint64, (var).as_gint64, __old.as_gint64) == __old.as_gint64; \
 225                 } while (0); \
 226         } while (0)
 227
 228 static inline void
 229 domains_lock (void)
 230 {
 231         mono_coop_mutex_lock (&threadpool->domains_lock);
 232 }
 233
 234 static inline void
 235 domains_unlock (void)
 236 {
 237         mono_coop_mutex_unlock (&threadpool->domains_lock);
 238 }
 239
 240 static gpointer
 241 rand_create (void)
 242 {
 243         mono_rand_open ();
 244         return mono_rand_init (NULL, 0);
 245 }
 246
 247 static guint32
 248 rand_next (gpointer *handle, guint32 min, guint32 max)
 249 {
 250         MonoError error;
 251         guint32 val;
 252         mono_rand_try_get_uint32 (handle, &val, min, max, &error);
 253         // FIXME handle error
 254         mono_error_assert_ok (&error);
 255         return val;
 256 }
 257
 258 static void
 259 rand_free (gpointer handle)
 260 {
 261         mono_rand_close (handle);
 262 }
 263
 264 static void
 265 initialize (void)
 266 {
 267         ThreadPoolHillClimbing *hc;
 268         const char *threads_per_cpu_env;
 269         gint threads_per_cpu;
 270         gint threads_count;
 271
 272         g_assert (!threadpool);
 273         threadpool = g_new0 (ThreadPool, 1);
 274         g_assert (threadpool);
 275
 276         threadpool->domains = g_ptr_array_new ();
 277         mono_coop_mutex_init (&threadpool->domains_lock);
 278
 279         threadpool->parked_threads_count = 0;
 280         mono_coop_cond_init (&threadpool->parked_threads_cond);
 281         threadpool->working_threads = g_ptr_array_new ();
 282         mono_coop_mutex_init (&threadpool->active_threads_lock);
 283
 284         threadpool->worker_creation_current_second = -1;
 285         mono_coop_mutex_init (&threadpool->worker_creation_lock);
 286
 287         threadpool->heuristic_adjustment_interval = 10;
 288         mono_coop_mutex_init (&threadpool->heuristic_lock);
 289
 290         mono_rand_open ();
 291
 292         hc = &threadpool->heuristic_hill_climbing;
 293
 294         hc->wave_period = HILL_CLIMBING_WAVE_PERIOD;
 295         hc->max_thread_wave_magnitude = HILL_CLIMBING_MAX_WAVE_MAGNITUDE;
 296         hc->thread_magnitude_multiplier = (gdouble) HILL_CLIMBING_WAVE_MAGNITUDE_MULTIPLIER;
 297         hc->samples_to_measure = hc->wave_period * HILL_CLIMBING_WAVE_HISTORY_SIZE;
 298         hc->target_throughput_ratio = (gdouble) HILL_CLIMBING_BIAS;
 299         hc->target_signal_to_noise_ratio = (gdouble) HILL_CLIMBING_TARGET_SIGNAL_TO_NOISE_RATIO;
 300         hc->max_change_per_second = (gdouble) HILL_CLIMBING_MAX_CHANGE_PER_SECOND;
 301         hc->max_change_per_sample = (gdouble) HILL_CLIMBING_MAX_CHANGE_PER_SAMPLE;
 302         hc->sample_interval_low = HILL_CLIMBING_SAMPLE_INTERVAL_LOW;
 303         hc->sample_interval_high = HILL_CLIMBING_SAMPLE_INTERVAL_HIGH;
 304         hc->throughput_error_smoothing_factor = (gdouble) HILL_CLIMBING_ERROR_SMOOTHING_FACTOR;
 305         hc->gain_exponent = (gdouble) HILL_CLIMBING_GAIN_EXPONENT;
 306         hc->max_sample_error = (gdouble) HILL_CLIMBING_MAX_SAMPLE_ERROR_PERCENT;
 307         hc->current_control_setting = 0;
 308         hc->total_samples = 0;
 309         hc->last_thread_count = 0;
 310         hc->average_throughput_noise = 0;
 311         hc->elapsed_since_last_change = 0;
 312         hc->accumulated_completion_count = 0;
 313         hc->accumulated_sample_duration = 0;
 314         hc->samples = g_new0 (gdouble, hc->samples_to_measure);
 315         hc->thread_counts = g_new0 (gdouble, hc->samples_to_measure);
 316         hc->random_interval_generator = rand_create ();
 317         hc->current_sample_interval = rand_next (&hc->random_interval_generator, hc->sample_interval_low, hc->sample_interval_high);
 318
 319         if (!(threads_per_cpu_env = g_getenv ("MONO_THREADS_PER_CPU")))
 320                 threads_per_cpu = 1;
 321         else
 322                 threads_per_cpu = CLAMP (atoi (threads_per_cpu_env), 1, 50);
 323
 324         threads_count = mono_cpu_count () * threads_per_cpu;
 325
 326         threadpool->limit_worker_min = threadpool->limit_io_min = threads_count;
 327
 328 #if defined (PLATFORM_ANDROID) || defined (HOST_IOS)
 329         threadpool->limit_worker_max = threadpool->limit_io_max = CLAMP (threads_count * 100, MIN (threads_count, 200), MAX (threads_count, 200));
 330 #else
 331         threadpool->limit_worker_max = threadpool->limit_io_max = threads_count * 100;
 332 #endif
 333
 334         threadpool->counters._.max_working = threadpool->limit_worker_min;
 335
 336         threadpool->cpu_usage_state = g_new0 (MonoCpuUsageState, 1);
 337
 338         threadpool->suspended = FALSE;
 339 }
 340
 341 static void worker_kill (ThreadPoolWorkingThread *thread);
 342
 343 static void
 344 cleanup (void)
 345 {
 346         guint i;
 347
 348         /* we make the assumption along the code that we are
 349          * cleaning up only if the runtime is shutting down */
 350         g_assert (mono_runtime_is_shutting_down ());
 351
 352         while (monitor_status != MONITOR_STATUS_NOT_RUNNING)
 353                 mono_thread_info_sleep (1, NULL);
 354
 355         mono_coop_mutex_lock (&threadpool->active_threads_lock);
 356
 357         /* stop all threadpool->working_threads */
 358         for (i = 0; i < threadpool->working_threads->len; ++i)
 359                 worker_kill ((ThreadPoolWorkingThread*) g_ptr_array_index (threadpool->working_threads, i));
 360
 361         /* unpark all threadpool->parked_threads */
 362         mono_coop_cond_broadcast (&threadpool->parked_threads_cond);
 363
 364         mono_coop_mutex_unlock (&threadpool->active_threads_lock);
 365 }
 366
 367 gboolean
 368 mono_threadpool_ms_enqueue_work_item (MonoDomain *domain, MonoObject *work_item, MonoError *error)
 369 {
 370         static MonoClass *threadpool_class = NULL;
 371         static MonoMethod *unsafe_queue_custom_work_item_method = NULL;
 372         MonoDomain *current_domain;
 373         MonoBoolean f;
 374         gpointer args [2];
 375
 376         mono_error_init (error);
 377         g_assert (work_item);
 378
 379         if (!threadpool_class)
 380                 threadpool_class = mono_class_load_from_name (mono_defaults.corlib, "System.Threading", "ThreadPool");
 381
 382         if (!unsafe_queue_custom_work_item_method)
 383                 unsafe_queue_custom_work_item_method = mono_class_get_method_from_name (threadpool_class, "UnsafeQueueCustomWorkItem", 2);
 384         g_assert (unsafe_queue_custom_work_item_method);
 385
 386         f = FALSE;
 387
 388         args [0] = (gpointer) work_item;
 389         args [1] = (gpointer) &f;
 390
 391         current_domain = mono_domain_get ();
 392         if (current_domain == domain) {
 393                 mono_runtime_invoke_checked (unsafe_queue_custom_work_item_method, NULL, args, error);
 394                 return_val_if_nok (error, FALSE);
 395         } else {
 396                 mono_thread_push_appdomain_ref (domain);
 397                 if (mono_domain_set (domain, FALSE)) {
 398                         mono_runtime_invoke_checked (unsafe_queue_custom_work_item_method, NULL, args, error);
 399                         if (!is_ok (error)) {
 400                                 mono_thread_pop_appdomain_ref ();
 401                                 return FALSE;
 402                         }
 403                         mono_domain_set (current_domain, TRUE);
 404                 }
 405                 mono_thread_pop_appdomain_ref ();
 406         }
 407         return TRUE;
 408 }
 409
 410 /* LOCKING: domains_lock must be held */
 411 static void
 412 tpdomain_add (ThreadPoolDomain *tpdomain)
 413 {
 414         guint i, len;
 415
 416         g_assert (tpdomain);
 417
 418         len = threadpool->domains->len;
 419         for (i = 0; i < len; ++i) {
 420                 if (g_ptr_array_index (threadpool->domains, i) == tpdomain)
 421                         break;
 422         }
 423
 424         if (i == len)
 425                 g_ptr_array_add (threadpool->domains, tpdomain);
 426 }
 427
 428 /* LOCKING: domains_lock must be held. */
 429 static gboolean
 430 tpdomain_remove (ThreadPoolDomain *tpdomain)
 431 {
 432         g_assert (tpdomain);
 433         return g_ptr_array_remove (threadpool->domains, tpdomain);
 434 }
 435
 436 /* LOCKING: domains_lock must be held */
 437 static ThreadPoolDomain *
 438 tpdomain_get (MonoDomain *domain, gboolean create)
 439 {
 440         guint i;
 441         ThreadPoolDomain *tpdomain;
 442
 443         g_assert (domain);
 444
 445         for (i = 0; i < threadpool->domains->len; ++i) {
 446                 ThreadPoolDomain *tpdomain;
 447
 448                 tpdomain = (ThreadPoolDomain *)g_ptr_array_index (threadpool->domains, i);
 449                 if (tpdomain->domain == domain)
 450                         return tpdomain;
 451         }
 452
 453         if (!create)
 454                 return NULL;
 455
 456         tpdomain = g_new0 (ThreadPoolDomain, 1);
 457         tpdomain->domain = domain;
 458         mono_coop_cond_init (&tpdomain->cleanup_cond);
 459
 460         tpdomain_add (tpdomain);
 461
 462         return tpdomain;
 463 }
 464
 465 static void
 466 tpdomain_free (ThreadPoolDomain *tpdomain)
 467 {
 468         g_free (tpdomain);
 469 }
 470
 471 /* LOCKING: domains_lock must be held */
 472 static gboolean
 473 domain_any_has_request (void)
 474 {
 475         guint i;
 476
 477         for (i = 0; i < threadpool->domains->len; ++i) {
 478                 ThreadPoolDomain *tmp = (ThreadPoolDomain *)g_ptr_array_index (threadpool->domains, i);
 479                 if (tmp->outstanding_request > 0)
 480                         return TRUE;
 481         }
 482
 483         return FALSE;
 484 }
 485
 486 /* LOCKING: domains_lock must be held */
 487 static ThreadPoolDomain *
 488 tpdomain_get_next (ThreadPoolDomain *current)
 489 {
 490         ThreadPoolDomain *tpdomain = NULL;
 491         guint len;
 492
 493         len = threadpool->domains->len;
 494         if (len > 0) {
 495                 guint i, current_idx = -1;
 496                 if (current) {
 497                         for (i = 0; i < len; ++i) {
 498                                 if (current == g_ptr_array_index (threadpool->domains, i)) {
 499                                         current_idx = i;
 500                                         break;
 501                                 }
 502                         }
 503                         g_assert (current_idx != (guint)-1);
 504                 }
 505                 for (i = current_idx + 1; i < len + current_idx + 1; ++i) {
 506                         ThreadPoolDomain *tmp = (ThreadPoolDomain *)g_ptr_array_index (threadpool->domains, i % len);
 507                         if (tmp->outstanding_request > 0) {
 508                                 tpdomain = tmp;
 509                                 break;
 510                         }
 511                 }
 512         }
 513
 514         return tpdomain;
 515 }
 516
 517 static void
 518 worker_wait_interrupt (gpointer data)
 519 {
 520         mono_coop_mutex_lock (&threadpool->active_threads_lock);
 521         mono_coop_cond_signal (&threadpool->parked_threads_cond);
 522         mono_coop_mutex_unlock (&threadpool->active_threads_lock);
 523 }
 524
 525 /* return TRUE if timeout, FALSE otherwise (worker unpark or interrupt) */
 526 static gboolean
 527 worker_park (void)
 528 {
 529         gboolean timeout = FALSE;
 530
 531         mono_trace (G_LOG_LEVEL_DEBUG, MONO_TRACE_THREADPOOL, "[%p] current worker parking", mono_native_thread_id_get ());
 532
 533         mono_gc_set_skip_thread (TRUE);
 534
 535         mono_coop_mutex_lock (&threadpool->active_threads_lock);
 536
 537         if (!mono_runtime_is_shutting_down ()) {
 538                 static gpointer rand_handle = NULL;
 539                 MonoInternalThread *thread_internal;
 540                 gboolean interrupted = FALSE;
 541
 542                 if (!rand_handle)
 543                         rand_handle = rand_create ();
 544                 g_assert (rand_handle);
 545
 546                 thread_internal = mono_thread_internal_current ();
 547                 g_assert (thread_internal);
 548
 549                 threadpool->parked_threads_count += 1;
 550                 g_ptr_array_remove_fast (threadpool->working_threads, thread_internal);
 551
 552                 mono_thread_info_install_interrupt (worker_wait_interrupt, NULL, &interrupted);
 553                 if (interrupted)
 554                         goto done;
 555
 556                 if (mono_coop_cond_timedwait (&threadpool->parked_threads_cond, &threadpool->active_threads_lock, rand_next (&rand_handle, 5 * 1000, 60 * 1000)) != 0)
 557                         timeout = TRUE;
 558
 559                 mono_thread_info_uninstall_interrupt (&interrupted);
 560
 561 done:
 562                 g_ptr_array_add (threadpool->working_threads, thread_internal);
 563                 threadpool->parked_threads_count -= 1;
 564         }
 565
 566         mono_coop_mutex_unlock (&threadpool->active_threads_lock);
 567
 568         mono_gc_set_skip_thread (FALSE);
 569
 570         mono_trace (G_LOG_LEVEL_DEBUG, MONO_TRACE_THREADPOOL, "[%p] current worker unparking, timeout? %s", mono_native_thread_id_get (), timeout ? "yes" : "no");
 571
 572         return timeout;
 573 }
 574
 575 static gboolean
 576 worker_try_unpark (void)
 577 {
 578         gboolean res = FALSE;
 579
 580         mono_trace (G_LOG_LEVEL_DEBUG, MONO_TRACE_THREADPOOL, "[%p] try unpark worker", mono_native_thread_id_get ());
 581
 582         mono_coop_mutex_lock (&threadpool->active_threads_lock);
 583         if (threadpool->parked_threads_count > 0) {
 584                 mono_coop_cond_signal (&threadpool->parked_threads_cond);
 585                 res = TRUE;
 586         }
 587         mono_coop_mutex_unlock (&threadpool->active_threads_lock);
 588
 589         mono_trace (G_LOG_LEVEL_DEBUG, MONO_TRACE_THREADPOOL, "[%p] try unpark worker, success? %s", mono_native_thread_id_get (), res ? "yes" : "no");
 590
 591         return res;
 592 }
 593
 594 static void
 595 worker_kill (ThreadPoolWorkingThread *thread)
 596 {
 597         if (thread == mono_thread_internal_current ())
 598                 return;
 599
 600         mono_thread_internal_abort ((MonoInternalThread*) thread);
 601 }
 602
 603 static void
 604 worker_thread (gpointer data)
 605 {
 606         MonoError error;
 607         MonoInternalThread *thread;
 608         ThreadPoolDomain *tpdomain, *previous_tpdomain;
 609         ThreadPoolCounter counter;
 610         gboolean retire = FALSE;
 611
 612         mono_trace (G_LOG_LEVEL_INFO, MONO_TRACE_THREADPOOL, "[%p] worker starting", mono_native_thread_id_get ());
 613
 614         g_assert (threadpool);
 615
 616         thread = mono_thread_internal_current ();
 617         g_assert (thread);
 618
 619         mono_thread_set_name_internal (thread, mono_string_new (mono_get_root_domain (), "Threadpool worker"), FALSE, &error);
 620         mono_error_assert_ok (&error);
 621
 622         mono_coop_mutex_lock (&threadpool->active_threads_lock);
 623         g_ptr_array_add (threadpool->working_threads, thread);
 624         mono_coop_mutex_unlock (&threadpool->active_threads_lock);
 625
 626         previous_tpdomain = NULL;
 627
 628         domains_lock ();
 629
 630         while (!mono_runtime_is_shutting_down ()) {
 631                 tpdomain = NULL;
 632
 633                 if ((thread->state & (ThreadState_AbortRequested | ThreadState_SuspendRequested)) != 0) {
 634                         domains_unlock ();
 635                         mono_thread_interruption_checkpoint ();
 636                         domains_lock ();
 637                 }
 638
 639                 if (retire || !(tpdomain = tpdomain_get_next (previous_tpdomain))) {
 640                         gboolean timeout;
 641
 642                         COUNTER_ATOMIC (counter, {
 643                                 counter._.working --;
 644                                 counter._.parked ++;
 645                         });
 646
 647                         domains_unlock ();
 648                         timeout = worker_park ();
 649                         domains_lock ();
 650
 651                         COUNTER_ATOMIC (counter, {
 652                                 counter._.working ++;
 653                                 counter._.parked --;
 654                         });
 655
 656                         if (timeout)
 657                                 break;
 658
 659                         if (retire)
 660                                 retire = FALSE;
 661
 662                         /* The tpdomain->domain might have unloaded, while this thread was parked */
 663                         previous_tpdomain = NULL;
 664
 665                         continue;
 666                 }
 667
 668                 tpdomain->outstanding_request --;
 669                 g_assert (tpdomain->outstanding_request >= 0);
 670
 671                 mono_trace (G_LOG_LEVEL_DEBUG, MONO_TRACE_THREADPOOL, "[%p] worker running in domain %p (outstanding requests %d) ",
 672                         mono_native_thread_id_get (), tpdomain->domain, tpdomain->outstanding_request);
 673
 674                 g_assert (tpdomain->domain);
 675                 g_assert (tpdomain->threadpool_jobs >= 0);
 676                 tpdomain->threadpool_jobs ++;
 677
 678                 /*
 679                  * This is needed so there is always an lmf frame in the runtime invoke call below,
 680                  * so ThreadAbortExceptions are caught even if the thread is in native code.
 681                  */
 682                 mono_defaults.threadpool_perform_wait_callback_method->save_lmf = TRUE;
 683
 684                 domains_unlock ();
 685
 686                 mono_thread_push_appdomain_ref (tpdomain->domain);
 687                 if (mono_domain_set (tpdomain->domain, FALSE)) {
 688                         MonoObject *exc = NULL, *res;
 689
 690                         res = mono_runtime_try_invoke (mono_defaults.threadpool_perform_wait_callback_method, NULL, NULL, &exc, &error);
 691                         if (exc || !mono_error_ok(&error)) {
 692                                 if (exc == NULL)
 693                                         exc = (MonoObject *) mono_error_convert_to_exception (&error);
 694                                 else
 695                                         mono_error_cleanup (&error);
 696                                 mono_thread_internal_unhandled_exception (exc);
 697                         } else if (res && *(MonoBoolean*) mono_object_unbox (res) == FALSE)
 698                                 retire = TRUE;
 699
 700                         mono_thread_clr_state (thread, (MonoThreadState)~ThreadState_Background);
 701                         if (!mono_thread_test_state (thread , ThreadState_Background))
 702                                 ves_icall_System_Threading_Thread_SetState (thread, ThreadState_Background);
 703
 704                         mono_domain_set (mono_get_root_domain (), TRUE);
 705                 }
 706                 mono_thread_pop_appdomain_ref ();
 707
 708                 domains_lock ();
 709
 710                 tpdomain->threadpool_jobs --;
 711                 g_assert (tpdomain->threadpool_jobs >= 0);
 712
 713                 if (tpdomain->outstanding_request + tpdomain->threadpool_jobs == 0 && mono_domain_is_unloading (tpdomain->domain)) {
 714                         gboolean removed;
 715
 716                         removed = tpdomain_remove (tpdomain);
 717                         g_assert (removed);
 718
 719                         mono_coop_cond_signal (&tpdomain->cleanup_cond);
 720                         tpdomain = NULL;
 721                 }
 722
 723                 previous_tpdomain = tpdomain;
 724         }
 725
 726         domains_unlock ();
 727
 728         mono_coop_mutex_lock (&threadpool->active_threads_lock);
 729         g_ptr_array_remove_fast (threadpool->working_threads, thread);
 730         mono_coop_mutex_unlock (&threadpool->active_threads_lock);
 731
 732         COUNTER_ATOMIC (counter, {
 733                 counter._.working--;
 734                 counter._.active --;
 735         });
 736
 737         mono_trace (G_LOG_LEVEL_INFO, MONO_TRACE_THREADPOOL, "[%p] worker finishing", mono_native_thread_id_get ());
 738 }
 739
 740 static gboolean
 741 worker_try_create (void)
 742 {
 743         ThreadPoolCounter counter;
 744         MonoInternalThread *thread;
 745         gint64 current_ticks;
 746         gint32 now;
 747
 748         mono_coop_mutex_lock (&threadpool->worker_creation_lock);
 749
 750         mono_trace (G_LOG_LEVEL_DEBUG, MONO_TRACE_THREADPOOL, "[%p] try create worker", mono_native_thread_id_get ());
 751         current_ticks = mono_100ns_ticks ();
 752         now = current_ticks / (10 * 1000 * 1000);
 753         if (0 == current_ticks) {
 754                 g_warning ("failed to get 100ns ticks");
 755         } else {
 756                 if (threadpool->worker_creation_current_second != now) {
 757                         threadpool->worker_creation_current_second = now;
 758                         threadpool->worker_creation_current_count = 0;
 759                 } else {
 760                         g_assert (threadpool->worker_creation_current_count <= WORKER_CREATION_MAX_PER_SEC);
 761                         if (threadpool->worker_creation_current_count == WORKER_CREATION_MAX_PER_SEC) {
 762                                 mono_trace (G_LOG_LEVEL_DEBUG, MONO_TRACE_THREADPOOL, "[%p] try create worker, failed: maximum number of worker created per second reached, current count = %d",
 763                                         mono_native_thread_id_get (), threadpool->worker_creation_current_count);
 764                                 mono_coop_mutex_unlock (&threadpool->worker_creation_lock);
 765                                 return FALSE;
 766                         }
 767                 }
 768         }
 769
 770         COUNTER_ATOMIC (counter, {
 771                 if (counter._.working >= counter._.max_working) {
 772                         mono_trace (G_LOG_LEVEL_DEBUG, MONO_TRACE_THREADPOOL, "[%p] try create worker, failed: maximum number of working threads reached",
 773                                 mono_native_thread_id_get ());
 774                         mono_coop_mutex_unlock (&threadpool->worker_creation_lock);
 775                         return FALSE;
 776                 }
 777                 counter._.working ++;
 778                 counter._.active ++;
 779         });
 780
 781         MonoError error;
 782         if ((thread = mono_thread_create_internal (mono_get_root_domain (), worker_thread, NULL, TRUE, 0, &error)) != NULL) {
 783                 threadpool->worker_creation_current_count += 1;
 784
 785                 mono_trace (G_LOG_LEVEL_DEBUG, MONO_TRACE_THREADPOOL, "[%p] try create worker, created %p, now = %d count = %d", mono_native_thread_id_get (), GUINT_TO_POINTER(thread->tid), now, threadpool->worker_creation_current_count);
 786                 mono_coop_mutex_unlock (&threadpool->worker_creation_lock);
 787                 return TRUE;
 788         }
 789
 790         mono_trace (G_LOG_LEVEL_DEBUG, MONO_TRACE_THREADPOOL, "[%p] try create worker, failed: could not create thread due to %s", mono_native_thread_id_get (), mono_error_get_message (&error));
 791         mono_error_cleanup (&error);
 792
 793         COUNTER_ATOMIC (counter, {
 794                 counter._.working --;
 795                 counter._.active --;
 796         });
 797
 798         mono_coop_mutex_unlock (&threadpool->worker_creation_lock);
 799         return FALSE;
 800 }
 801
 802 static void monitor_ensure_running (void);
 803
 804 static gboolean
 805 worker_request (MonoDomain *domain)
 806 {
 807         ThreadPoolDomain *tpdomain;
 808
 809         g_assert (domain);
 810         g_assert (threadpool);
 811
 812         if (mono_runtime_is_shutting_down ())
 813                 return FALSE;
 814
 815         domains_lock ();
 816
 817         /* synchronize check with worker_thread */
 818         if (mono_domain_is_unloading (domain)) {
 819                 domains_unlock ();
 820                 return FALSE;
 821         }
 822
 823         tpdomain = tpdomain_get (domain, TRUE);
 824         g_assert (tpdomain);
 825         tpdomain->outstanding_request ++;
 826
 827         mono_trace (G_LOG_LEVEL_DEBUG, MONO_TRACE_THREADPOOL, "[%p] request worker, domain = %p, outstanding_request = %d",
 828                 mono_native_thread_id_get (), tpdomain->domain, tpdomain->outstanding_request);
 829
 830         domains_unlock ();
 831
 832         if (threadpool->suspended)
 833                 return FALSE;
 834
 835         monitor_ensure_running ();
 836
 837         if (worker_try_unpark ()) {
 838                 mono_trace (G_LOG_LEVEL_DEBUG, MONO_TRACE_THREADPOOL, "[%p] request worker, unparked", mono_native_thread_id_get ());
 839                 return TRUE;
 840         }
 841
 842         if (worker_try_create ()) {
 843                 mono_trace (G_LOG_LEVEL_DEBUG, MONO_TRACE_THREADPOOL, "[%p] request worker, created", mono_native_thread_id_get ());
 844                 return TRUE;
 845         }
 846
 847         mono_trace (G_LOG_LEVEL_DEBUG, MONO_TRACE_THREADPOOL, "[%p] request worker, failed", mono_native_thread_id_get ());
 848         return FALSE;
 849 }
 850
 851 static gboolean
 852 monitor_should_keep_running (void)
 853 {
 854         static gint64 last_should_keep_running = -1;
 855
 856         g_assert (monitor_status == MONITOR_STATUS_WAITING_FOR_REQUEST || monitor_status == MONITOR_STATUS_REQUESTED);
 857
 858         if (InterlockedExchange (&monitor_status, MONITOR_STATUS_WAITING_FOR_REQUEST) == MONITOR_STATUS_WAITING_FOR_REQUEST) {
 859                 gboolean should_keep_running = TRUE, force_should_keep_running = FALSE;
 860
 861                 if (mono_runtime_is_shutting_down ()) {
 862                         should_keep_running = FALSE;
 863                 } else {
 864                         domains_lock ();
 865                         if (!domain_any_has_request ())
 866                                 should_keep_running = FALSE;
 867                         domains_unlock ();
 868
 869                         if (!should_keep_running) {
 870                                 if (last_should_keep_running == -1 || mono_100ns_ticks () - last_should_keep_running < MONITOR_MINIMAL_LIFETIME * 1000 * 10) {
 871                                         should_keep_running = force_should_keep_running = TRUE;
 872                                 }
 873                         }
 874                 }
 875
 876                 if (should_keep_running) {
 877                         if (last_should_keep_running == -1 || !force_should_keep_running)
 878                                 last_should_keep_running = mono_100ns_ticks ();
 879                 } else {
 880                         last_should_keep_running = -1;
 881                         if (InterlockedCompareExchange (&monitor_status, MONITOR_STATUS_NOT_RUNNING, MONITOR_STATUS_WAITING_FOR_REQUEST) == MONITOR_STATUS_WAITING_FOR_REQUEST)
 882                                 return FALSE;
 883                 }
 884         }
 885
 886         g_assert (monitor_status == MONITOR_STATUS_WAITING_FOR_REQUEST || monitor_status == MONITOR_STATUS_REQUESTED);
 887
 888         return TRUE;
 889 }
 890
 891 static gboolean
 892 monitor_sufficient_delay_since_last_dequeue (void)
 893 {
 894         gint64 threshold;
 895
 896         g_assert (threadpool);
 897
 898         if (threadpool->cpu_usage < CPU_USAGE_LOW) {
 899                 threshold = MONITOR_INTERVAL;
 900         } else {
 901                 ThreadPoolCounter counter;
 902                 counter.as_gint64 = COUNTER_READ();
 903                 threshold = counter._.max_working * MONITOR_INTERVAL * 2;
 904         }
 905
 906         return mono_msec_ticks () >= threadpool->heuristic_last_dequeue + threshold;
 907 }
 908
 909 static void hill_climbing_force_change (gint16 new_thread_count, ThreadPoolHeuristicStateTransition transition);
 910
 911 static void
 912 monitor_thread (void)
 913 {
 914         MonoInternalThread *current_thread = mono_thread_internal_current ();
 915         guint i;
 916
 917         mono_cpu_usage (threadpool->cpu_usage_state);
 918
 919         mono_trace (G_LOG_LEVEL_DEBUG, MONO_TRACE_THREADPOOL, "[%p] monitor thread, started", mono_native_thread_id_get ());
 920
 921         do {
 922                 ThreadPoolCounter counter;
 923                 gboolean limit_worker_max_reached;
 924                 gint32 interval_left = MONITOR_INTERVAL;
 925                 gint32 awake = 0; /* number of spurious awakes we tolerate before doing a round of rebalancing */
 926
 927                 g_assert (monitor_status != MONITOR_STATUS_NOT_RUNNING);
 928
 929                 mono_gc_set_skip_thread (TRUE);
 930
 931                 do {
 932                         gint64 ts;
 933                         gboolean alerted = FALSE;
 934
 935                         if (mono_runtime_is_shutting_down ())
 936                                 break;
 937
 938                         ts = mono_msec_ticks ();
 939                         if (mono_thread_info_sleep (interval_left, &alerted) == 0)
 940                                 break;
 941                         interval_left -= mono_msec_ticks () - ts;
 942
 943                         mono_gc_set_skip_thread (FALSE);
 944                         if ((current_thread->state & (ThreadState_StopRequested | ThreadState_SuspendRequested)) != 0)
 945                                 mono_thread_interruption_checkpoint ();
 946                         mono_gc_set_skip_thread (TRUE);
 947                 } while (interval_left > 0 && ++awake < 10);
 948
 949                 mono_gc_set_skip_thread (FALSE);
 950
 951                 if (threadpool->suspended)
 952                         continue;
 953
 954                 if (mono_runtime_is_shutting_down ())
 955                         continue;
 956
 957                 domains_lock ();
 958                 if (!domain_any_has_request ()) {
 959                         domains_unlock ();
 960                         continue;
 961                 }
 962                 domains_unlock ();
 963
 964                 threadpool->cpu_usage = mono_cpu_usage (threadpool->cpu_usage_state);
 965
 966                 if (!monitor_sufficient_delay_since_last_dequeue ())
 967                         continue;
 968
 969                 limit_worker_max_reached = FALSE;
 970
 971                 COUNTER_ATOMIC (counter, {
 972                         if (counter._.max_working >= threadpool->limit_worker_max) {
 973                                 limit_worker_max_reached = TRUE;
 974                                 break;
 975                         }
 976                         counter._.max_working ++;
 977                 });
 978
 979                 if (limit_worker_max_reached)
 980                         continue;
 981
 982                 hill_climbing_force_change (counter._.max_working, TRANSITION_STARVATION);
 983
 984                 for (i = 0; i < 5; ++i) {
 985                         if (mono_runtime_is_shutting_down ())
 986                                 break;
 987
 988                         if (worker_try_unpark ()) {
 989                                 mono_trace (G_LOG_LEVEL_DEBUG, MONO_TRACE_THREADPOOL, "[%p] monitor thread, unparked", mono_native_thread_id_get ());
 990                                 break;
 991                         }
 992
 993                         if (worker_try_create ()) {
 994                                 mono_trace (G_LOG_LEVEL_DEBUG, MONO_TRACE_THREADPOOL, "[%p] monitor thread, created", mono_native_thread_id_get ());
 995                                 break;
 996                         }
 997                 }
 998         } while (monitor_should_keep_running ());
 999
1000         mono_trace (G_LOG_LEVEL_DEBUG, MONO_TRACE_THREADPOOL, "[%p] monitor thread, finished", mono_native_thread_id_get ());
1001 }
1002
1003 static void
1004 monitor_ensure_running (void)
1005 {
1006         MonoError error;
1007         for (;;) {
1008                 switch (monitor_status) {
1009                 case MONITOR_STATUS_REQUESTED:
1010                         return;
1011                 case MONITOR_STATUS_WAITING_FOR_REQUEST:
1012                         InterlockedCompareExchange (&monitor_status, MONITOR_STATUS_REQUESTED, MONITOR_STATUS_WAITING_FOR_REQUEST);
1013                         break;
1014                 case MONITOR_STATUS_NOT_RUNNING:
1015                         if (mono_runtime_is_shutting_down ())
1016                                 return;
1017                         if (InterlockedCompareExchange (&monitor_status, MONITOR_STATUS_REQUESTED, MONITOR_STATUS_NOT_RUNNING) == MONITOR_STATUS_NOT_RUNNING) {
1018                                 if (!mono_thread_create_internal (mono_get_root_domain (), monitor_thread, NULL, TRUE, SMALL_STACK, &error)) {
1019                                         monitor_status = MONITOR_STATUS_NOT_RUNNING;
1020                                         mono_error_cleanup (&error);
1021                                 }
1022                                 return;
1023                         }
1024                         break;
1025                 default: g_assert_not_reached ();
1026                 }
1027         }
1028 }
1029
1030 static void
1031 hill_climbing_change_thread_count (gint16 new_thread_count, ThreadPoolHeuristicStateTransition transition)
1032 {
1033         ThreadPoolHillClimbing *hc;
1034
1035         g_assert (threadpool);
1036
1037         hc = &threadpool->heuristic_hill_climbing;
1038
1039         mono_trace (G_LOG_LEVEL_INFO, MONO_TRACE_THREADPOOL, "[%p] hill climbing, change max number of threads %d", mono_native_thread_id_get (), new_thread_count);
1040
1041         hc->last_thread_count = new_thread_count;
1042         hc->current_sample_interval = rand_next (&hc->random_interval_generator, hc->sample_interval_low, hc->sample_interval_high);
1043         hc->elapsed_since_last_change = 0;
1044         hc->completions_since_last_change = 0;
1045 }
1046
1047 static void
1048 hill_climbing_force_change (gint16 new_thread_count, ThreadPoolHeuristicStateTransition transition)
1049 {
1050         ThreadPoolHillClimbing *hc;
1051
1052         g_assert (threadpool);
1053
1054         hc = &threadpool->heuristic_hill_climbing;
1055
1056         if (new_thread_count != hc->last_thread_count) {
1057                 hc->current_control_setting += new_thread_count - hc->last_thread_count;
1058                 hill_climbing_change_thread_count (new_thread_count, transition);
1059         }
1060 }
1061
1062 static double_complex
1063 hill_climbing_get_wave_component (gdouble *samples, guint sample_count, gdouble period)
1064 {
1065         ThreadPoolHillClimbing *hc;
1066         gdouble w, cosine, sine, coeff, q0, q1, q2;
1067         guint i;
1068
1069         g_assert (threadpool);
1070         g_assert (sample_count >= period);
1071         g_assert (period >= 2);
1072
1073         hc = &threadpool->heuristic_hill_climbing;
1074
1075         w = 2.0 * M_PI / period;
1076         cosine = cos (w);
1077         sine = sin (w);
1078         coeff = 2.0 * cosine;
1079         q0 = q1 = q2 = 0;
1080
1081         for (i = 0; i < sample_count; ++i) {
1082                 q0 = coeff * q1 - q2 + samples [(hc->total_samples - sample_count + i) % hc->samples_to_measure];
1083                 q2 = q1;
1084                 q1 = q0;
1085         }
1086
1087         return mono_double_complex_scalar_div (mono_double_complex_make (q1 - q2 * cosine, (q2 * sine)), ((gdouble)sample_count));
1088 }
1089
1090 static gint16
1091 hill_climbing_update (gint16 current_thread_count, guint32 sample_duration, gint32 completions, gint64 *adjustment_interval)
1092 {
1093         ThreadPoolHillClimbing *hc;
1094         ThreadPoolHeuristicStateTransition transition;
1095         gdouble throughput;
1096         gdouble throughput_error_estimate;
1097         gdouble confidence;
1098         gdouble move;
1099         gdouble gain;
1100         gint sample_index;
1101         gint sample_count;
1102         gint new_thread_wave_magnitude;
1103         gint new_thread_count;
1104         double_complex thread_wave_component;
1105         double_complex throughput_wave_component;
1106         double_complex ratio;
1107
1108         g_assert (threadpool);
1109         g_assert (adjustment_interval);
1110
1111         hc = &threadpool->heuristic_hill_climbing;
1112
1113         /* If someone changed the thread count without telling us, update our records accordingly. */
1114         if (current_thread_count != hc->last_thread_count)
1115                 hill_climbing_force_change (current_thread_count, TRANSITION_INITIALIZING);
1116
1117         /* Update the cumulative stats for this thread count */
1118         hc->elapsed_since_last_change += sample_duration;
1119         hc->completions_since_last_change += completions;
1120
1121         /* Add in any data we've already collected about this sample */
1122         sample_duration += hc->accumulated_sample_duration;
1123         completions += hc->accumulated_completion_count;
1124
1125         /* We need to make sure we're collecting reasonably accurate data. Since we're just counting the end
1126          * of each work item, we are goinng to be missing some data about what really happened during the
1127          * sample interval. The count produced by each thread includes an initial work item that may have
1128          * started well before the start of the interval, and each thread may have been running some new
1129          * work item for some time before the end of the interval, which did not yet get counted. So
1130          * our count is going to be off by +/- threadCount workitems.
1131          *
1132          * The exception is that the thread that reported to us last time definitely wasn't running any work
1133          * at that time, and the thread that's reporting now definitely isn't running a work item now. So
1134          * we really only need to consider threadCount-1 threads.
1135          *
1136          * Thus the percent error in our count is +/- (threadCount-1)/numCompletions.
1137          *
1138          * We cannot rely on the frequency-domain analysis we'll be doing later to filter out this error, because
1139          * of the way it accumulates over time. If this sample is off by, say, 33% in the negative direction,
1140          * then the next one likely will be too. The one after that will include the sum of the completions
1141          * we missed in the previous samples, and so will be 33% positive. So every three samples we'll have
1142          * two "low" samples and one "high" sample. This will appear as periodic variation right in the frequency
1143          * range we're targeting, which will not be filtered by the frequency-domain translation. */
1144         if (hc->total_samples > 0 && ((current_thread_count - 1.0) / completions) >= hc->max_sample_error) {
1145                 /* Not accurate enough yet. Let's accumulate the data so
1146                  * far, and tell the ThreadPool to collect a little more. */
1147                 hc->accumulated_sample_duration = sample_duration;
1148                 hc->accumulated_completion_count = completions;
1149                 *adjustment_interval = 10;
1150                 return current_thread_count;
1151         }
1152
1153         /* We've got enouugh data for our sample; reset our accumulators for next time. */
1154         hc->accumulated_sample_duration = 0;
1155         hc->accumulated_completion_count = 0;
1156
1157         /* Add the current thread count and throughput sample to our history. */
1158         throughput = ((gdouble) completions) / sample_duration;
1159
1160         sample_index = hc->total_samples % hc->samples_to_measure;
1161         hc->samples [sample_index] = throughput;
1162         hc->thread_counts [sample_index] = current_thread_count;
1163         hc->total_samples ++;
1164
1165         /* Set up defaults for our metrics. */
1166         thread_wave_component = mono_double_complex_make(0, 0);
1167         throughput_wave_component = mono_double_complex_make(0, 0);
1168         throughput_error_estimate = 0;
1169         ratio = mono_double_complex_make(0, 0);
1170         confidence = 0;
1171
1172         transition = TRANSITION_WARMUP;
1173
1174         /* How many samples will we use? It must be at least the three wave periods we're looking for, and it must also
1175          * be a whole multiple of the primary wave's period; otherwise the frequency we're looking for will fall between
1176          * two frequency bands in the Fourier analysis, and we won't be able to measure it accurately. */
1177         sample_count = ((gint) MIN (hc->total_samples - 1, hc->samples_to_measure) / hc->wave_period) * hc->wave_period;
1178
1179         if (sample_count > hc->wave_period) {
1180                 guint i;
1181                 gdouble average_throughput;
1182                 gdouble average_thread_count;
1183                 gdouble sample_sum = 0;
1184                 gdouble thread_sum = 0;
1185
1186                 /* Average the throughput and thread count samples, so we can scale the wave magnitudes later. */
1187                 for (i = 0; i < sample_count; ++i) {
1188                         guint j = (hc->total_samples - sample_count + i) % hc->samples_to_measure;
1189                         sample_sum += hc->samples [j];
1190                         thread_sum += hc->thread_counts [j];
1191                 }
1192
1193                 average_throughput = sample_sum / sample_count;
1194                 average_thread_count = thread_sum / sample_count;
1195
1196                 if (average_throughput > 0 && average_thread_count > 0) {
1197                         gdouble noise_for_confidence, adjacent_period_1, adjacent_period_2;
1198
1199                         /* Calculate the periods of the adjacent frequency bands we'll be using to
1200                          * measure noise levels. We want the two adjacent Fourier frequency bands. */
1201                         adjacent_period_1 = sample_count / (((gdouble) sample_count) / ((gdouble) hc->wave_period) + 1);
1202                         adjacent_period_2 = sample_count / (((gdouble) sample_count) / ((gdouble) hc->wave_period) - 1);
1203
1204                         /* Get the the three different frequency components of the throughput (scaled by average
1205                          * throughput). Our "error" estimate (the amount of noise that might be present in the
1206                          * frequency band we're really interested in) is the average of the adjacent bands. */
1207                         throughput_wave_component = mono_double_complex_scalar_div (hill_climbing_get_wave_component (hc->samples, sample_count, hc->wave_period), average_throughput);
1208                         throughput_error_estimate = cabs (mono_double_complex_scalar_div (hill_climbing_get_wave_component (hc->samples, sample_count, adjacent_period_1), average_throughput));
1209
1210                         if (adjacent_period_2 <= sample_count) {
1211                                 throughput_error_estimate = MAX (throughput_error_estimate, cabs (mono_double_complex_scalar_div (hill_climbing_get_wave_component (
1212                                         hc->samples, sample_count, adjacent_period_2), average_throughput)));
1213                         }
1214
1215                         /* Do the same for the thread counts, so we have something to compare to. We don't
1216                          * measure thread count noise, because there is none; these are exact measurements. */
1217                         thread_wave_component = mono_double_complex_scalar_div (hill_climbing_get_wave_component (hc->thread_counts, sample_count, hc->wave_period), average_thread_count);
1218
1219                         /* Update our moving average of the throughput noise. We'll use this
1220                          * later as feedback to determine the new size of the thread wave. */
1221                         if (hc->average_throughput_noise == 0) {
1222                                 hc->average_throughput_noise = throughput_error_estimate;
1223                         } else {
1224                                 hc->average_throughput_noise = (hc->throughput_error_smoothing_factor * throughput_error_estimate)
1225                                         + ((1.0 + hc->throughput_error_smoothing_factor) * hc->average_throughput_noise);
1226                         }
1227
1228                         if (cabs (thread_wave_component) > 0) {
1229                                 /* Adjust the throughput wave so it's centered around the target wave,
1230                                  * and then calculate the adjusted throughput/thread ratio. */
1231                                 ratio = mono_double_complex_div (mono_double_complex_sub (throughput_wave_component, mono_double_complex_scalar_mul(thread_wave_component, hc->target_throughput_ratio)), thread_wave_component);
1232                                 transition = TRANSITION_CLIMBING_MOVE;
1233                         } else {
1234                                 ratio = mono_double_complex_make (0, 0);
1235                                 transition = TRANSITION_STABILIZING;
1236                         }
1237
1238                         noise_for_confidence = MAX (hc->average_throughput_noise, throughput_error_estimate);
1239                         if (noise_for_confidence > 0) {
1240                                 confidence = cabs (thread_wave_component) / noise_for_confidence / hc->target_signal_to_noise_ratio;
1241                         } else {
1242                                 /* there is no noise! */
1243                                 confidence = 1.0;
1244                         }
1245                 }
1246         }
1247
1248         /* We use just the real part of the complex ratio we just calculated. If the throughput signal
1249          * is exactly in phase with the thread signal, this will be the same as taking the magnitude of
1250          * the complex move and moving that far up. If they're 180 degrees out of phase, we'll move
1251          * backward (because this indicates that our changes are having the opposite of the intended effect).
1252          * If they're 90 degrees out of phase, we won't move at all, because we can't tell wether we're
1253          * having a negative or positive effect on throughput. */
1254         move = creal (ratio);
1255         move = CLAMP (move, -1.0, 1.0);
1256
1257         /* Apply our confidence multiplier. */
1258         move *= CLAMP (confidence, -1.0, 1.0);
1259
1260         /* Now apply non-linear gain, such that values around zero are attenuated, while higher values
1261          * are enhanced. This allows us to move quickly if we're far away from the target, but more slowly
1262         * if we're getting close, giving us rapid ramp-up without wild oscillations around the target. */
1263         gain = hc->max_change_per_second * sample_duration;
1264         move = pow (fabs (move), hc->gain_exponent) * (move >= 0.0 ? 1 : -1) * gain;
1265         move = MIN (move, hc->max_change_per_sample);
1266
1267         /* If the result was positive, and CPU is > 95%, refuse the move. */
1268         if (move > 0.0 && threadpool->cpu_usage > CPU_USAGE_HIGH)
1269                 move = 0.0;
1270
1271         /* Apply the move to our control setting. */
1272         hc->current_control_setting += move;
1273
1274         /* Calculate the new thread wave magnitude, which is based on the moving average we've been keeping of the
1275          * throughput error.  This average starts at zero, so we'll start with a nice safe little wave at first. */
1276         new_thread_wave_magnitude = (gint)(0.5 + (hc->current_control_setting * hc->average_throughput_noise
1277                 * hc->target_signal_to_noise_ratio * hc->thread_magnitude_multiplier * 2.0));
1278         new_thread_wave_magnitude = CLAMP (new_thread_wave_magnitude, 1, hc->max_thread_wave_magnitude);
1279
1280         /* Make sure our control setting is within the ThreadPool's limits. */
1281         hc->current_control_setting = CLAMP (hc->current_control_setting, threadpool->limit_worker_min, threadpool->limit_worker_max - new_thread_wave_magnitude);
1282
1283         /* Calculate the new thread count (control setting + square wave). */
1284         new_thread_count = (gint)(hc->current_control_setting + new_thread_wave_magnitude * ((hc->total_samples / (hc->wave_period / 2)) % 2));
1285
1286         /* Make sure the new thread count doesn't exceed the ThreadPool's limits. */
1287         new_thread_count = CLAMP (new_thread_count, threadpool->limit_worker_min, threadpool->limit_worker_max);
1288
1289         if (new_thread_count != current_thread_count)
1290                 hill_climbing_change_thread_count (new_thread_count, transition);
1291
1292         if (creal (ratio) < 0.0 && new_thread_count == threadpool->limit_worker_min)
1293                 *adjustment_interval = (gint)(0.5 + hc->current_sample_interval * (10.0 * MAX (-1.0 * creal (ratio), 1.0)));
1294         else
1295                 *adjustment_interval = hc->current_sample_interval;
1296
1297         return new_thread_count;
1298 }
1299
1300 static void
1301 heuristic_notify_work_completed (void)
1302 {
1303         g_assert (threadpool);
1304
1305         InterlockedIncrement (&threadpool->heuristic_completions);
1306         threadpool->heuristic_last_dequeue = mono_msec_ticks ();
1307 }
1308
1309 static gboolean
1310 heuristic_should_adjust (void)
1311 {
1312         g_assert (threadpool);
1313
1314         if (threadpool->heuristic_last_dequeue > threadpool->heuristic_last_adjustment + threadpool->heuristic_adjustment_interval) {
1315                 ThreadPoolCounter counter;
1316                 counter.as_gint64 = COUNTER_READ();
1317                 if (counter._.working <= counter._.max_working)
1318                         return TRUE;
1319         }
1320
1321         return FALSE;
1322 }
1323
1324 static void
1325 heuristic_adjust (void)
1326 {
1327         g_assert (threadpool);
1328
1329         if (mono_coop_mutex_trylock (&threadpool->heuristic_lock) == 0) {
1330                 gint32 completions = InterlockedExchange (&threadpool->heuristic_completions, 0);
1331                 gint64 sample_end = mono_msec_ticks ();
1332                 gint64 sample_duration = sample_end - threadpool->heuristic_sample_start;
1333
1334                 if (sample_duration >= threadpool->heuristic_adjustment_interval / 2) {
1335                         ThreadPoolCounter counter;
1336                         gint16 new_thread_count;
1337
1338                         counter.as_gint64 = COUNTER_READ ();
1339                         new_thread_count = hill_climbing_update (counter._.max_working, sample_duration, completions, &threadpool->heuristic_adjustment_interval);
1340
1341                         COUNTER_ATOMIC (counter, { counter._.max_working = new_thread_count; });
1342
1343                         if (new_thread_count > counter._.max_working)
1344                                 worker_request (mono_domain_get ());
1345
1346                         threadpool->heuristic_sample_start = sample_end;
1347                         threadpool->heuristic_last_adjustment = mono_msec_ticks ();
1348                 }
1349
1350                 mono_coop_mutex_unlock (&threadpool->heuristic_lock);
1351         }
1352 }
1353
1354 void
1355 mono_threadpool_ms_cleanup (void)
1356 {
1357 #ifndef DISABLE_SOCKETS
1358         mono_threadpool_ms_io_cleanup ();
1359 #endif
1360         mono_lazy_cleanup (&status, cleanup);
1361 }
1362
1363 MonoAsyncResult *
1364 mono_threadpool_ms_begin_invoke (MonoDomain *domain, MonoObject *target, MonoMethod *method, gpointer *params, MonoError *error)
1365 {
1366         static MonoClass *async_call_klass = NULL;
1367         MonoMethodMessage *message;
1368         MonoAsyncResult *async_result;
1369         MonoAsyncCall *async_call;
1370         MonoDelegate *async_callback = NULL;
1371         MonoObject *state = NULL;
1372
1373         if (!async_call_klass)
1374                 async_call_klass = mono_class_load_from_name (mono_defaults.corlib, "System", "MonoAsyncCall");
1375
1376         mono_lazy_initialize (&status, initialize);
1377
1378         mono_error_init (error);
1379
1380         message = mono_method_call_message_new (method, params, mono_get_delegate_invoke (method->klass), (params != NULL) ? (&async_callback) : NULL, (params != NULL) ? (&state) : NULL, error);
1381         return_val_if_nok (error, NULL);
1382
1383         async_call = (MonoAsyncCall*) mono_object_new_checked (domain, async_call_klass, error);
1384         return_val_if_nok (error, NULL);
1385
1386         MONO_OBJECT_SETREF (async_call, msg, message);
1387         MONO_OBJECT_SETREF (async_call, state, state);
1388
1389         if (async_callback) {
1390                 MONO_OBJECT_SETREF (async_call, cb_method, mono_get_delegate_invoke (((MonoObject*) async_callback)->vtable->klass));
1391                 MONO_OBJECT_SETREF (async_call, cb_target, async_callback);
1392         }
1393
1394         async_result = mono_async_result_new (domain, NULL, async_call->state, NULL, (MonoObject*) async_call, error);
1395         return_val_if_nok (error, NULL);
1396         MONO_OBJECT_SETREF (async_result, async_delegate, target);
1397
1398         mono_threadpool_ms_enqueue_work_item (domain, (MonoObject*) async_result, error);
1399         return_val_if_nok (error, NULL);
1400
1401         return async_result;
1402 }
1403
1404 MonoObject *
1405 mono_threadpool_ms_end_invoke (MonoAsyncResult *ares, MonoArray **out_args, MonoObject **exc, MonoError *error)
1406 {
1407         MonoAsyncCall *ac;
1408
1409         mono_error_init (error);
1410         g_assert (exc);
1411         g_assert (out_args);
1412
1413         *exc = NULL;
1414         *out_args = NULL;
1415
1416         /* check if already finished */
1417         mono_monitor_enter ((MonoObject*) ares);
1418
1419         if (ares->endinvoke_called) {
1420                 mono_error_set_invalid_operation(error, "Delegate EndInvoke method called more than once");
1421                 mono_monitor_exit ((MonoObject*) ares);
1422                 return NULL;
1423         }
1424
1425         ares->endinvoke_called = 1;
1426
1427         /* wait until we are really finished */
1428         if (ares->completed) {
1429                 mono_monitor_exit ((MonoObject *) ares);
1430         } else {
1431                 gpointer wait_event;
1432                 if (ares->handle) {
1433                         wait_event = mono_wait_handle_get_handle ((MonoWaitHandle*) ares->handle);
1434                 } else {
1435                         wait_event = mono_w32event_create (TRUE, FALSE);
1436                         g_assert(wait_event);
1437                         MonoWaitHandle *wait_handle = mono_wait_handle_new (mono_object_domain (ares), wait_event, error);
1438                         if (!is_ok (error)) {
1439                                 CloseHandle (wait_event);
1440                                 return NULL;
1441                         }
1442                         MONO_OBJECT_SETREF (ares, handle, (MonoObject*) wait_handle);
1443                 }
1444                 mono_monitor_exit ((MonoObject*) ares);
1445                 MONO_ENTER_GC_SAFE;
1446 #ifdef HOST_WIN32
1447                 WaitForSingleObjectEx (wait_event, INFINITE, TRUE);
1448 #else
1449                 mono_w32handle_wait_one (wait_event, INFINITE, TRUE);
1450 #endif
1451                 MONO_EXIT_GC_SAFE;
1452         }
1453
1454         ac = (MonoAsyncCall*) ares->object_data;
1455         g_assert (ac);
1456
1457         *exc = ac->msg->exc; /* FIXME: GC add write barrier */
1458         *out_args = ac->out_args;
1459         return ac->res;
1460 }
1461
1462 gboolean
1463 mono_threadpool_ms_remove_domain_jobs (MonoDomain *domain, int timeout)
1464 {
1465         gint64 end;
1466         ThreadPoolDomain *tpdomain;
1467         gboolean ret;
1468
1469         g_assert (domain);
1470         g_assert (timeout >= -1);
1471
1472         g_assert (mono_domain_is_unloading (domain));
1473
1474         if (timeout != -1)
1475                 end = mono_msec_ticks () + timeout;
1476
1477 #ifndef DISABLE_SOCKETS
1478         mono_threadpool_ms_io_remove_domain_jobs (domain);
1479         if (timeout != -1) {
1480                 if (mono_msec_ticks () > end)
1481                         return FALSE;
1482         }
1483 #endif
1484
1485         /*
1486          * Wait for all threads which execute jobs in the domain to exit.
1487          * The is_unloading () check in worker_request () ensures that
1488          * no new jobs are added after we enter the lock below.
1489          */
1490         mono_lazy_initialize (&status, initialize);
1491         domains_lock ();
1492
1493         tpdomain = tpdomain_get (domain, FALSE);
1494         if (!tpdomain) {
1495                 domains_unlock ();
1496                 return TRUE;
1497         }
1498
1499         ret = TRUE;
1500
1501         while (tpdomain->outstanding_request + tpdomain->threadpool_jobs > 0) {
1502                 if (timeout == -1) {
1503                         mono_coop_cond_wait (&tpdomain->cleanup_cond, &threadpool->domains_lock);
1504                 } else {
1505                         gint64 now;
1506                         gint res;
1507
1508                         now = mono_msec_ticks();
1509                         if (now > end) {
1510                                 ret = FALSE;
1511                                 break;
1512                         }
1513
1514                         res = mono_coop_cond_timedwait (&tpdomain->cleanup_cond, &threadpool->domains_lock, end - now);
1515                         if (res != 0) {
1516                                 ret = FALSE;
1517                                 break;
1518                         }
1519                 }
1520         }
1521
1522         /* Remove from the list the worker threads look at */
1523         tpdomain_remove (tpdomain);
1524
1525         domains_unlock ();
1526
1527         mono_coop_cond_destroy (&tpdomain->cleanup_cond);
1528         tpdomain_free (tpdomain);
1529
1530         return ret;
1531 }
1532
1533 void
1534 mono_threadpool_ms_suspend (void)
1535 {
1536         if (threadpool)
1537                 threadpool->suspended = TRUE;
1538 }
1539
1540 void
1541 mono_threadpool_ms_resume (void)
1542 {
1543         if (threadpool)
1544                 threadpool->suspended = FALSE;
1545 }
1546
1547 void
1548 ves_icall_System_Threading_ThreadPool_GetAvailableThreadsNative (gint32 *worker_threads, gint32 *completion_port_threads)
1549 {
1550         ThreadPoolCounter counter;
1551
1552         if (!worker_threads || !completion_port_threads)
1553                 return;
1554
1555         mono_lazy_initialize (&status, initialize);
1556
1557         counter.as_gint64 = COUNTER_READ ();
1558
1559         *worker_threads = MAX (0, threadpool->limit_worker_max - counter._.active);
1560         *completion_port_threads = threadpool->limit_io_max;
1561 }
1562
1563 void
1564 ves_icall_System_Threading_ThreadPool_GetMinThreadsNative (gint32 *worker_threads, gint32 *completion_port_threads)
1565 {
1566         if (!worker_threads || !completion_port_threads)
1567                 return;
1568
1569         mono_lazy_initialize (&status, initialize);
1570
1571         *worker_threads = threadpool->limit_worker_min;
1572         *completion_port_threads = threadpool->limit_io_min;
1573 }
1574
1575 void
1576 ves_icall_System_Threading_ThreadPool_GetMaxThreadsNative (gint32 *worker_threads, gint32 *completion_port_threads)
1577 {
1578         if (!worker_threads || !completion_port_threads)
1579                 return;
1580
1581         mono_lazy_initialize (&status, initialize);
1582
1583         *worker_threads = threadpool->limit_worker_max;
1584         *completion_port_threads = threadpool->limit_io_max;
1585 }
1586
1587 MonoBoolean
1588 ves_icall_System_Threading_ThreadPool_SetMinThreadsNative (gint32 worker_threads, gint32 completion_port_threads)
1589 {
1590         mono_lazy_initialize (&status, initialize);
1591
1592         if (worker_threads <= 0 || worker_threads > threadpool->limit_worker_max)
1593                 return FALSE;
1594         if (completion_port_threads <= 0 || completion_port_threads > threadpool->limit_io_max)
1595                 return FALSE;
1596
1597         threadpool->limit_worker_min = worker_threads;
1598         threadpool->limit_io_min = completion_port_threads;
1599
1600         return TRUE;
1601 }
1602
1603 MonoBoolean
1604 ves_icall_System_Threading_ThreadPool_SetMaxThreadsNative (gint32 worker_threads, gint32 completion_port_threads)
1605 {
1606         gint cpu_count = mono_cpu_count ();
1607
1608         mono_lazy_initialize (&status, initialize);
1609
1610         if (worker_threads < threadpool->limit_worker_min || worker_threads < cpu_count)
1611                 return FALSE;
1612         if (completion_port_threads < threadpool->limit_io_min || completion_port_threads < cpu_count)
1613                 return FALSE;
1614
1615         threadpool->limit_worker_max = worker_threads;
1616         threadpool->limit_io_max = completion_port_threads;
1617
1618         return TRUE;
1619 }
1620
1621 void
1622 ves_icall_System_Threading_ThreadPool_InitializeVMTp (MonoBoolean *enable_worker_tracking)
1623 {
1624         if (enable_worker_tracking) {
1625                 // TODO implement some kind of switch to have the possibily to use it
1626                 *enable_worker_tracking = FALSE;
1627         }
1628
1629         mono_lazy_initialize (&status, initialize);
1630 }
1631
1632 MonoBoolean
1633 ves_icall_System_Threading_ThreadPool_NotifyWorkItemComplete (void)
1634 {
1635         ThreadPoolCounter counter;
1636
1637         if (mono_domain_is_unloading (mono_domain_get ()) || mono_runtime_is_shutting_down ())
1638                 return FALSE;
1639
1640         heuristic_notify_work_completed ();
1641
1642         if (heuristic_should_adjust ())
1643                 heuristic_adjust ();
1644
1645         counter.as_gint64 = COUNTER_READ ();
1646         return counter._.working <= counter._.max_working;
1647 }
1648
1649 void
1650 ves_icall_System_Threading_ThreadPool_NotifyWorkItemProgressNative (void)
1651 {
1652         heuristic_notify_work_completed ();
1653
1654         if (heuristic_should_adjust ())
1655                 heuristic_adjust ();
1656 }
1657
1658 void
1659 ves_icall_System_Threading_ThreadPool_ReportThreadStatus (MonoBoolean is_working)
1660 {
1661         // TODO
1662         MonoError error;
1663         mono_error_set_not_implemented (&error, "");
1664         mono_error_set_pending_exception (&error);
1665 }
1666
1667 MonoBoolean
1668 ves_icall_System_Threading_ThreadPool_RequestWorkerThread (void)
1669 {
1670         return worker_request (mono_domain_get ());
1671 }
1672
1673 MonoBoolean G_GNUC_UNUSED
1674 ves_icall_System_Threading_ThreadPool_PostQueuedCompletionStatus (MonoNativeOverlapped *native_overlapped)
1675 {
1676         /* This copy the behavior of the current Mono implementation */
1677         MonoError error;
1678         mono_error_set_not_implemented (&error, "");
1679         mono_error_set_pending_exception (&error);
1680         return FALSE;
1681 }
1682
1683 MonoBoolean G_GNUC_UNUSED
1684 ves_icall_System_Threading_ThreadPool_BindIOCompletionCallbackNative (gpointer file_handle)
1685 {
1686         /* This copy the behavior of the current Mono implementation */
1687         return TRUE;
1688 }
1689
1690 MonoBoolean G_GNUC_UNUSED
1691 ves_icall_System_Threading_ThreadPool_IsThreadPoolHosted (void)
1692 {
1693         return FALSE;
1694 }