[sgen] Optional scanning without the small bitmap fast path.

To experiment with different optimization combinations.

diff --git a/mono/metadata/sgen-marksweep.c b/mono/metadata/sgen-marksweep.c
index 0c595b40db7a5b8aa5e5c7572dc02d275faddefa..aa71b53ae72ff7a9a1f5fcc8831dae7ab54815b3 100644 (file)
--- a/mono/metadata/sgen-marksweep.c
+++ b/mono/metadata/sgen-marksweep.c
@@ -1134,6 +1134,7 @@ major_get_and_reset_num_major_objects_marked (void)
 
 #if !defined (FIXED_HEAP) && !defined (SGEN_PARALLEL_MARK)
 //#define USE_PREFETCH_QUEUE
+#define DESCRIPTOR_FAST_PATH
 
 #ifdef HEAVY_STATISTICS
 static long long stat_optimized_copy;
@@ -1150,8 +1151,10 @@ static long long stat_optimized_major_mark;
 static long long stat_optimized_major_mark_small;
 static long long stat_optimized_major_mark_large;
 static long long stat_optimized_major_scan;
+#ifdef DESCRIPTOR_FAST_PATH
 static long long stat_optimized_major_scan_fast;
 static long long stat_optimized_major_scan_slow;
+#endif
 
 static long long stat_drain_prefetch_fills;
 static long long stat_drain_prefetch_fill_failures;
@@ -1360,6 +1363,7 @@ drain_gray_stack (ScanCopyContext ctx)
                HEAVY_STAT (++stat_optimized_major_scan);
 
                /* Now scan the object. */
+#ifdef DESCRIPTOR_FAST_PATH
                if (type == DESC_TYPE_SMALL_BITMAP) {
                        void **_objptr = (void**)(obj);
                        gsize _bmap = (desc) >> 16;
@@ -1391,6 +1395,29 @@ drain_gray_stack (ScanCopyContext ctx)
                        HEAVY_STAT (++stat_optimized_major_scan_slow);
                        major_scan_object_no_mark (obj, desc, queue);
                }
+#else
+#undef HANDLE_PTR
+#define HANDLE_PTR(ptr,obj)    do {                                    \
+                       void *__old = *(ptr);                           \
+                       if (__old) {                                    \
+                               gboolean __still_in_nursery = optimized_copy_or_mark_object ((ptr), __old, queue); \
+                               if (G_UNLIKELY (__still_in_nursery && !sgen_ptr_in_nursery ((ptr)) && !SGEN_OBJECT_IS_CEMENTED (*(ptr)))) { \
+                                       void *__copy = *(ptr);          \
+                                       sgen_add_to_global_remset ((ptr), __copy); \
+                               }                                       \
+                       }                                               \
+               } while (0)
+
+               {
+                       char *start = obj;
+#ifdef HEAVY_STATISTICS
+                       sgen_descriptor_count_scanned_object (desc);
+                       add_scanned_object (start);
+#endif
+
+#include "sgen-scan-object.h"
+               }
+#endif
        }
 }
 #endif
@@ -2482,8 +2509,10 @@ sgen_marksweep_init_internal (SgenMajorCollector *collector, gboolean is_concurr
        mono_counters_register ("Optimized major mark small", MONO_COUNTER_GC | MONO_COUNTER_LONG, &stat_optimized_major_mark_small);
        mono_counters_register ("Optimized major mark large", MONO_COUNTER_GC | MONO_COUNTER_LONG, &stat_optimized_major_mark_large);
        mono_counters_register ("Optimized major scan", MONO_COUNTER_GC | MONO_COUNTER_LONG, &stat_optimized_major_scan);
+#ifdef DESCRIPTOR_FAST_PATH
        mono_counters_register ("Optimized major scan slow", MONO_COUNTER_GC | MONO_COUNTER_LONG, &stat_optimized_major_scan_slow);
        mono_counters_register ("Optimized major scan fast", MONO_COUNTER_GC | MONO_COUNTER_LONG, &stat_optimized_major_scan_fast);
+#endif
 
        mono_counters_register ("Gray stack drain loops", MONO_COUNTER_GC | MONO_COUNTER_LONG, &stat_drain_loops);
        mono_counters_register ("Gray stack prefetch fills", MONO_COUNTER_GC | MONO_COUNTER_LONG, &stat_drain_prefetch_fills);