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AFNElJ9Eo9KbQuhqxV8cFRJGb9Z/Hvb+aLYAVAhleM+b4RUpJS2bIikELnvIsLw35TGvoXsufAdDRmVW0fIjptf+/5Yh@vger.kernel.org X-Gm-Message-State: AOJu0YysOQIARKqhc7etz7TzDYFSry39UnKGo1a9Amgb4SZqNzTkT6iN JfeJxTmdA4+vPwun8/Oowm7YlVZtGAbIDDSWtUBEA1uBRHbtkhl+pdspVhwGeDEvtViu3RA3Z9+ r0NKrI5gkXg== X-Received: from pjre11.prod.google.com ([2002:a17:90a:b38b:b0:35d:ae01:8b69]) (user=irogers job=prod-delivery.src-stubby-dispatcher) by 2002:a17:90b:4c8c:b0:35f:c1cc:fef0 with SMTP id 98e67ed59e1d1-36140473e42mr11974997a91.13.1776643228258; Sun, 19 Apr 2026 17:00:28 -0700 (PDT) Date: Sun, 19 Apr 2026 16:58:41 -0700 In-Reply-To: <20260419235911.2186050-1-irogers@google.com> Precedence: bulk X-Mailing-List: linux-perf-users@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20260419235911.2186050-1-irogers@google.com> X-Mailer: git-send-email 2.54.0.rc1.513.gad8abe7a5a-goog Message-ID: <20260419235911.2186050-30-irogers@google.com> Subject: [PATCH v1 29/58] perf futex-contention: Port futex-contention to use python module From: Ian Rogers To: Peter Zijlstra , Ingo Molnar , Arnaldo Carvalho de Melo , Namhyung Kim , Jiri Olsa , Adrian Hunter , James Clark , Alice Rogers , Suzuki K Poulose , Mike Leach , John Garry , Leo Yan , Yicong Yang , Jonathan Cameron , Nick Terrell , David Sterba , Nathan Chancellor , Nick Desaulniers , Bill Wendling , Justin Stitt , Alexandre Chartre , Dmitrii Dolgov <9erthalion6@gmail.com>, Yuzhuo Jing , Blake Jones , Changbin Du , Gautam Menghani , Wangyang Guo , Pan Deng , Zhiguo Zhou , Tianyou Li , Thomas Falcon , Athira Rajeev , Collin Funk , Dapeng Mi , Ravi Bangoria , Zecheng Li , tanze , Thomas Richter , Ankur Arora , "Tycho Andersen (AMD)" , Howard Chu , Sun Jian , Derek Foreman , Swapnil Sapkal , Anubhav Shelat , Ricky Ringler , Qinxin Xia , Aditya Bodkhe , Chun-Tse Shao , Stephen Brennan , Yang Li , Chuck Lever , Chen Ni , linux-kernel@vger.kernel.org, linux-perf-users@vger.kernel.org, coresight@lists.linaro.org, linux-arm-kernel@lists.infradead.org Cc: Ian Rogers Content-Type: text/plain; charset="UTF-8" Rewrite tools/perf/scripts/python/futex-contention.py to use the python module and various style changes. By avoiding the overheads in the `perf script` execution the performance improves by more than 3.2x as shown in the following (with PYTHON_PATH and PERF_EXEC_PATH set as necessary): ``` $ perf record -e syscalls:sys_*_futex -a sleep 1 ... $ time perf script tools/perf/scripts/python/futex-contention.py Install the python-audit package to get syscall names. For example: # apt-get install python3-audit (Ubuntu) # yum install python3-audit (Fedora) etc. Press control+C to stop and show the summary aaa/4[2435653] lock 7f76b380c878 contended 1 times, 1099 avg ns [max: 1099 ns, min 1099 ns] ... real 0m1.007s user 0m0.935s sys 0m0.072s $ time python3 tools/perf/python/futex-contention.py ... real 0m0.314s user 0m0.259s sys 0m0.056s ``` Signed-off-by: Ian Rogers --- tools/perf/python/futex-contention.py | 54 +++++++++++++++++++++++++++ 1 file changed, 54 insertions(+) create mode 100755 tools/perf/python/futex-contention.py diff --git a/tools/perf/python/futex-contention.py b/tools/perf/python/futex-contention.py new file mode 100755 index 000000000000..153583de9cde --- /dev/null +++ b/tools/perf/python/futex-contention.py @@ -0,0 +1,54 @@ +#!/usr/bin/env python3 +# SPDX-License-Identifier: GPL-2.0 +# Measures futex contention. +from collections import defaultdict +from typing import Dict +import perf + +process_names: Dict[int, str] = {} +start_times: Dict[int, [int, int]] = {} +session = None +durations: Dict[[int, int], list] = defaultdict(list) + +FUTEX_WAIT = 0 +FUTEX_WAKE = 1 +FUTEX_PRIVATE_FLAG = 128 +FUTEX_CLOCK_REALTIME = 256 +FUTEX_CMD_MASK = ~(FUTEX_PRIVATE_FLAG | FUTEX_CLOCK_REALTIME) + + +def process_event(sample): + def handle_start(tid: int, uaddr: int, op: int, start_time: int) -> None: + if (op & FUTEX_CMD_MASK) != FUTEX_WAIT: + return + if tid not in process_names: + try: + process = session.process(tid) + except Exception: + return + process_names[tid] = process.comm() + start_times[tid] = (uaddr, start_time) + + def handle_end(tid: int, end_time: int) -> None: + if tid not in start_times: + return + (uaddr, start_time) = start_times[tid] + del start_times[tid] + durations[(tid, uaddr)].append(end_time - start_time) + event_name = str(sample.evsel) + if event_name == "evsel(syscalls:sys_enter_futex)": + handle_start(sample.sample_tid, sample.uaddr, + sample.op, sample.sample_time) + elif event_name == "evsel(syscalls:sys_exit_futex)": + handle_end(sample.sample_tid, sample.sample_time) + + +if __name__ == "__main__": + session = perf.session(perf.data("perf.data"), sample=process_event) + session.process_events() + for ((tid, uaddr), vals) in sorted(durations.items()): + avg = sum(vals) / len(vals) + max_val = max(vals) + min_val = min(vals) + print(f"{process_names[tid]}[{tid}] lock {uaddr:x} contended {len(vals)} " + f"times, {avg} avg ns [max: {max_val} ns, min {min_val} ns]") -- 2.54.0.rc1.513.gad8abe7a5a-goog