Add stats for marking

Author: markshannon

Python/specialize.c

@@ -231,6 +231,8 @@ print_gc_stats(FILE *out, GCStats *stats)
         fprintf(out, "GC[%d] collections: %" PRIu64 "\n", i, stats[i].collections);
         fprintf(out, "GC[%d] object visits: %" PRIu64 "\n", i, stats[i].object_visits);
         fprintf(out, "GC[%d] objects collected: %" PRIu64 "\n", i, stats[i].objects_collected);
+        fprintf(out, "GC[%d] objects reachable from roots: %" PRIu64 "\n", i, stats[i].objects_transitively_reachable);
+        fprintf(out, "GC[%d] objects not reachable from roots: %" PRIu64 "\n", i, stats[i].objects_not_transitively_reachable);
     }
 }
 

Tools/scripts/summarize_stats.py

@@ -1118,6 +1118,8 @@ def calc_gc_stats(stats: Stats) -> Rows:
                 Count(gen["collections"]),
                 Count(gen["objects collected"]),
                 Count(gen["object visits"]),
+                Count(gen["objects reachable from roots"]),
+                Count(gen["objects not reachable from roots"]),
             )
             for (i, gen) in enumerate(gc_stats)
         ]
@@ -1127,7 +1129,8 @@ def calc_gc_stats(stats: Stats) -> Rows:
         "GC collections and effectiveness",
         [
             Table(
-                ("Generation:", "Collections:", "Objects collected:", "Object visits:"),
+                ("Generation:", "Collections:", "Objects collected:", "Object visits:",
+                 "Reachable from roots:", "Not reachable from roots:"),
                 calc_gc_stats,
             )
         ],