sergey-miryanov

| Command | Runs (n) | A collections pauses (n) | A collections young (n) | A collections middle (n) | A collections old (n) | A per run, median gc (ms) | A per run, median cov (%) | A per run, median share (%) | A per run, median gap (ms) | A per pause P99 (ms) | A per pause max (ms) | A collected P99 (obj) | A collected max (obj) | A empty (%) | B collections pauses (n) | B collections young (n) | B collections middle (n) | B collections old (n) | B per run, median gc (ms) | B per run, median cov (%) | B per run, median share (%) | B per run, median gap (ms) | B per pause P99 (ms) | B per pause max (ms) | B collected P99 (obj) | B collected max (obj) | B empty (%) | delta on gc B/A | delta on gc margin | Loops | |----------------------------------|----------|--------------------------|-------------------------|--------------------------|-----------------------|---------------------------|---------------------------|-----------------------------|----------------------------|-----

sergey-miryanov

[
{"name": "process_name", "ph": "M", "pid": 6480, "args": {"name": "Parent Process"}},
{"name": "GC Pause", "cat": "gc.pause", "ph": "X", "ts": 480394753063, "dur": 0, "pid": 13448, "tid": 0, "args": {"generation": 1, "iid": 0, "collections": 9, "heap_size": 15741, "collected": 176, "uncollectable": 0, "candidates": 15421, "object_visits": 109128, "objects_transitively_reachable": 18110, "objects_not_transitively_reachable": 1170, "work_to_do": -16464}},
{"name": "GC Pause (gen=1)", "cat": "gc.pause(gen=1)", "ph": "X", "ts": 480394753063, "dur": 0, "pid": 13448, "tid": 0, "args": {"generation": 1, "iid": 0, "collections": 9, "heap_size": 15741, "collected": 176, "uncollectable": 0, "candidates": 15421, "object_visits": 109128, "objects_transitively_reachable": 18110, "objects_not_transitively_reachable": 1170, "work_to_do": -16464}},
{"name": "Heap Size", "cat": "gc.heap_size", "ph": "C", "ts": 480394753063, "pid": 13448, "tid": 0, "args": {"heap_size": 15741}},
{"name": "G1", "cat": "gc.memory(gen=1)", "ph"

sergey-miryanov

import gc
import json
import os
import sys
import _gc_monitor as m
import time

if len(sys.argv) == 2:
    pid = int(sys.argv[-1])
else:

sergey-miryanov

import collections.abc
import gc
import random
import sys
import statistics
import time
import pyperf

# Adapted from https://gist.github.com/stedolan/4369a0fa27820e27d6e56bee5e412896
# See https://github.com/ocaml/ocaml/pull/10195

sergey-miryanov

2026-01-28 results

I compare different versions:

• main (29f1e778faaa31479e4ef84e2fb37a7a53984550)
• main+revert(+ https://github.com/sergey-miryanov/cpython/commit/efd2a4c0447496396445a5b5acc63a0482f1790d)
• main+gc-fix(+ https://github.com/sergey-miryanov/cpython/commits/gc-fix?author=sergey-miryanov)

I did comparison of pyperformance and gc-bench. gc-bench is pyperf-ed version of yours gc_big and gc_big_tree. Results are following:

sergey-miryanov

import httpx
import psutil
import asyncio
import gc
import os


def get_rss():
    p = psutil.Process()
    mem_info = p.memory_info()

sergey-miryanov

#!/usr/bin/env ./python
import contextlib
import os
import sys
import shutil
import subprocess
import time
import venv
from pathlib import Path
import tempfile

sergey-miryanov

import gc
import time
import statistics

# Adapted from https://gist.github.com/stedolan/4369a0fa27820e27d6e56bee5e412896
# See https://github.com/ocaml/ocaml/pull/10195
#
# In Python (free threading), this uses closer to 1.9 GiB of memory isntead of 800 MiB

# perf stat -e L1-dcache-loads,L1-dcache-load-misses,LLC-loads,LLC-load-misses ./python gc_big_800m.py

sergey-miryanov

import sys
import gc
import random
import time
import collections.abc
import statistics

# perf stat -e L1-dcache-loads,L1-dcache-load-misses,LLC-loads,LLC-load-misses ./python gc_big_tree.py
# perf stat -e l3_request_g1.caching_l3_cache_accesses,l3_comb_clstr_state.request_miss ./python gc_big_tree.py

sergey-miryanov

asyncio

async generator's finalization is broken

import asyncio
work_done = False

async def cursor():
 try: