GC.stat for concurrent set rebuilds

Author: luke-gruber

concurrent_set.c

@@ -105,6 +105,22 @@ concurrent_set_probe_next(struct concurrent_set_probe *probe)
     return probe->idx;
 }
 
+static inline unsigned long long time_diff_ns(struct timespec before, struct timespec after) {
+    unsigned long long total = 0;
+    total += (after.tv_nsec - before.tv_nsec);
+    total += (after.tv_sec - before.tv_sec) * (1000 * 1000 * 1000);
+    return total;
+}
+
+static inline void gettime(struct timespec *time) {
+    if (clock_gettime(CLOCK_MONOTONIC, time) == -1) {
+        rb_sys_fail("clock_gettime");
+    }
+}
+
+unsigned long long rb_concur_set_resize_time_taken_ns;
+unsigned int rb_concur_set_resize_serial;
+
 static void
 concurrent_set_try_resize_without_locking(VALUE old_set_obj, VALUE *set_obj_ptr)
 {
@@ -113,6 +129,10 @@ concurrent_set_try_resize_without_locking(VALUE old_set_obj, VALUE *set_obj_ptr)
         return;
     }
 
+    struct timespec resize_time_start;
+    struct timespec resize_time_end;
+    gettime(&resize_time_start);
+
     struct concurrent_set *old_set = RTYPEDDATA_GET_DATA(old_set_obj);
 
     // This may overcount by up to the number of threads concurrently attempting to insert
@@ -177,6 +197,10 @@ concurrent_set_try_resize_without_locking(VALUE old_set_obj, VALUE *set_obj_ptr)
     RUBY_ATOMIC_VALUE_SET(*set_obj_ptr, new_set_obj);
 
     RB_GC_GUARD(old_set_obj);
+    gettime(&resize_time_end);
+
+    rb_concur_set_resize_time_taken_ns += time_diff_ns(resize_time_start, resize_time_end);
+    rb_concur_set_resize_serial++;
 }
 
 static void

gc/default/default.c

@@ -7439,6 +7439,9 @@ enum gc_stat_sym {
     gc_stat_sym_gc_barrier_time_taken_ns,
     gc_stat_sym_gc_barrier_serial,
 
+    gc_stat_sym_concurrent_set_resize_time_taken_ns,
+    gc_stat_sym_concurrent_set_resize_serial,
+
 #if RGENGC_PROFILE
     gc_stat_sym_total_generated_normal_object_count,
     gc_stat_sym_total_generated_shady_object_count,
@@ -7490,10 +7493,14 @@ setup_gc_stat_symbols(void)
         S(oldmalloc_increase_bytes_limit);
 #endif
         S(weak_references_count);
+
         S(barrier_time_taken_ns);
         S(barrier_serial);
         S(gc_barrier_time_taken_ns);
         S(gc_barrier_serial);
+
+        S(concurrent_set_resize_time_taken_ns);
+        S(concurrent_set_resize_serial);
 #if RGENGC_PROFILE
         S(total_generated_normal_object_count);
         S(total_generated_shady_object_count);
@@ -7573,6 +7580,9 @@ rb_gc_impl_stat(void *objspace_ptr, VALUE hash_or_sym)
     SET(gc_barrier_time_taken_ns, ULL2NUM(rb_gc_barrier_time_taken_ns));
     SET(gc_barrier_serial, UINT2NUM(rb_gc_barrier_serial));
 
+    SET(concurrent_set_resize_time_taken_ns, ULL2NUM(rb_concur_set_resize_time_taken_ns));
+    SET(concurrent_set_resize_serial, UINT2NUM(rb_concur_set_resize_serial));
+
 #if RGENGC_ESTIMATE_OLDMALLOC
     SET(oldmalloc_increase_bytes, objspace->rgengc.oldmalloc_increase);
     SET(oldmalloc_increase_bytes_limit, objspace->rgengc.oldmalloc_increase_limit);

vm_core.h

@@ -838,6 +838,8 @@ typedef struct rb_vm_struct {
 RUBY_EXTERN unsigned long long rb_barrier_time_taken_ns;
 RUBY_EXTERN unsigned long long rb_gc_barrier_time_taken_ns;
 RUBY_EXTERN unsigned int rb_gc_barrier_serial;
+RUBY_EXTERN unsigned int rb_concur_set_resize_serial;
+RUBY_EXTERN unsigned long long rb_concur_set_resize_time_taken_ns;
 
 /* default values */