Revert alternating collections. Do incremental collection directly after young collection.

markshannon · markshannon · commit af24cd72c8cc · 2023-08-12T17:40:05.000+01:00
diff --git a/Include/internal/pycore_gc.h b/Include/internal/pycore_gc.h
@@ -205,7 +205,6 @@ struct _gc_runtime_state {
     Py_ssize_t incremental_gc_progress;
     /* Which of the old spaces is the aging space */
     int aging_space;
-    int incremental_next;
 };
 
 
diff --git a/Include/internal/pycore_runtime_init.h b/Include/internal/pycore_runtime_init.h
@@ -150,7 +150,7 @@ extern PyTypeObject _PyExc_MemoryError;
         }, \
         .gc = { \
             .enabled = 1, \
-            .young = { .threshold = 1000, }, \
+            .young = { .threshold = 2000, }, \
             .old = { \
                 { .threshold = 10, }, \
                 { .threshold = 10, }, \
diff --git a/Modules/gcmodule.c b/Modules/gcmodule.c
@@ -2526,28 +2526,36 @@ _Py_RunGC(PyThreadState *tstate)
     if (_py_stats) {
         _py_stats->object_stats.object_visits = 0;
     }
-    int stats_gen = gcstate->incremental_next ? NUM_GENERATIONS : 0;
 #endif
 
     gcstate->collecting = 1;
     struct gc_collection_stats stats = { 0 };
+    GC_STAT_ADD(0, collections, 1);
 
-    GC_STAT_ADD(stats_gen, collections, 1);
+    invoke_gc_callback(gcstate, "start", 0, &stats);
+    gc_collect_young(tstate, &stats);
+    invoke_gc_callback(gcstate, "stop", 0, &stats);
+    GC_STAT_ADD(0, objects_collected, stats.collected);
 
-    invoke_gc_callback(gcstate, "start", gcstate->incremental_next, &stats);
-    if (gcstate->incremental_next) {
-        gc_collect_increment(tstate, &stats);
-        gcstate->young.count = 0;
-    }
-    else {
-        gc_collect_young(tstate, &stats);
+#ifdef Py_STATS
+    if (_py_stats) {
+        GC_STAT_ADD(0, object_visits,
+            _py_stats->object_stats.object_visits);
+        _py_stats->object_stats.object_visits = 0;
     }
-    invoke_gc_callback(gcstate, "stop", gcstate->incremental_next, &stats);
+#endif
+
+    stats = (struct gc_collection_stats){ 0 };
+    GC_STAT_ADD(1, collections, 1);
+
+    invoke_gc_callback(gcstate, "start", 0, &stats);
+    gc_collect_increment(tstate, &stats);
+    invoke_gc_callback(gcstate, "stop", 0, &stats);
+    GC_STAT_ADD(1, objects_collected, stats.collected);
 
-    GC_STAT_ADD(stats_gen, objects_collected, stats.collected);
 #ifdef Py_STATS
     if (_py_stats) {
-        GC_STAT_ADD(stats_gen, object_visits,
+        GC_STAT_ADD(1, object_visits,
             _py_stats->object_stats.object_visits);
         _py_stats->object_stats.object_visits = 0;
     }
diff --git a/Python/specialize.c b/Python/specialize.c
@@ -208,6 +208,7 @@ print_gc_stats(FILE *out, GCStats *stats)
 {
     for (int i = 0; i < NUM_GENERATIONS+1; i++) {
         fprintf(out, "GC[%d] collections: %" PRIu64 "\n", i, stats[i].collections);
+        fprintf(out, "GC[%d] objects queued: %" PRIu64 "\n", i, stats[i].objects_queued);
         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);
     }
diff --git a/Tools/scripts/summarize_stats.py b/Tools/scripts/summarize_stats.py
@@ -506,7 +506,7 @@ def calculate_gc_stats(stats):
             gc_stats.append({})
         gc_stats[gen_n][name] = value
     return [
-        (i, gen["collections"], gen["objects collected"], gen["object visits"])
+        (i, gen["collections"], gen["objects queued"], gen["objects collected"], gen["object visits"])
         for (i, gen) in enumerate(gc_stats)
     ]
 
@@ -524,7 +524,7 @@ def emit_comparative_object_stats(base_stats, head_stats):
 def emit_gc_stats(stats):
     with Section("GC stats", summary="GC collections and effectiveness"):
         rows = calculate_gc_stats(stats)
-        emit_table(("Generation:",  "Collections:", "Objects collected:", "Object visits:"), rows)
+        emit_table(("Generation:",  "Collections:", "Objects queued:", "Objects collected:", "Object visits:"), rows)
 
 def emit_comparative_gc_stats(base_stats, head_stats):
     with Section("GC stats", summary="GC collections and effectiveness"):
@@ -533,6 +533,7 @@ def emit_comparative_gc_stats(base_stats, head_stats):
         emit_table(
             ("Generation:",
             "Base collections:", "Head collections:",
+            "Base objects queued:", "Head objects queued:",
             "Base objects collected:", "Head objects collected:",
             "Base object visits:", "Head object visits:"),
             join_rows(base_rows, head_rows))

Original file line number	Diff line number	Diff line change
`@@ -208,6 +208,7 @@ print_gc_stats(FILE out, GCStats stats)`
`208`	`208`	`{`
`209`	`209`	`for (int i = 0; i < NUM_GENERATIONS+1; i++) {`
`210`	`210`	`fprintf(out, "GC[%d] collections: %" PRIu64 "\n", i, stats[i].collections);`
	`211`	`+ fprintf(out, "GC[%d] objects queued: %" PRIu64 "\n", i, stats[i].objects_queued);`
`211`	`212`	`fprintf(out, "GC[%d] object visits: %" PRIu64 "\n", i, stats[i].object_visits);`
`212`	`213`	`fprintf(out, "GC[%d] objects collected: %" PRIu64 "\n", i, stats[i].objects_collected);`
`213`	`214`	`}`