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AFNElJ+TzSDcYU/B6A2nwYkdLH2RJVeTA7cD13fH6Qw1Em2tUqTpWPYimtUjlf26vVRIYBipt0+DUUmpMBjyJzltGlev@vger.kernel.org X-Gm-Message-State: AOJu0Yyz9jCmBg8S5iH0GSlIX3PppUqOgp2iqnEIrw85TEMOhIZHfL6h 8dvAHvm8xINW/RhHXYu1MrZDLYF5vri8JalM6elNIaLFJ7Byh7OPAigrvqRF+bwFk71EcT5h5dH gOHafGQpCcg== X-Received: from dycpq4.prod.google.com ([2002:a05:7301:fd04:b0:2df:6abf:7cee]) (user=irogers job=prod-delivery.src-stubby-dispatcher) by 2002:a05:693c:2b12:b0:2d9:cfa6:3d34 with SMTP id 5a478bee46e88-2e478a3370fmr5034461eec.23.1776643278439; Sun, 19 Apr 2026 17:01:18 -0700 (PDT) Date: Sun, 19 Apr 2026 16:59:03 -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: <20260419235911.2186050-52-irogers@google.com> Subject: [PATCH v1 51/58] perf wakeup-latency: Port wakeup-latency 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" Port the legacy Perl script wakeup-latency.pl to a python script using the perf module in tools/perf/python. The new script uses a class-based architecture and leverages the perf.session API for event processing. It measures wakeup latency by tracking timestamps of sched:sched_wakeup and sched:sched_switch events. Complications: - Used min() and max() built-in functions instead of if blocks to satisfy pylint recommendations. - pylint warns about the module name not being snake_case, but it is kept for consistency with the original script name. Assisted-by: Gemini:gemini-3.1-pro-preview Signed-off-by: Ian Rogers --- tools/perf/python/wakeup-latency.py | 85 +++++++++++++++++++++++++++++ 1 file changed, 85 insertions(+) create mode 100755 tools/perf/python/wakeup-latency.py diff --git a/tools/perf/python/wakeup-latency.py b/tools/perf/python/wakeup-latency.py new file mode 100755 index 000000000000..109b751aefb3 --- /dev/null +++ b/tools/perf/python/wakeup-latency.py @@ -0,0 +1,85 @@ +#!/usr/bin/env python3 +# SPDX-License-Identifier: GPL-2.0-only +"""Display avg/min/max wakeup latency.""" + +import argparse +from collections import defaultdict +import sys +from typing import Optional, Dict +import perf + +class WakeupLatency: + """Tracks and displays wakeup latency statistics.""" + def __init__(self) -> None: + self.last_wakeup: Dict[int, int] = defaultdict(int) + self.max_wakeup_latency = 0 + self.min_wakeup_latency = 1000000000 + self.total_wakeup_latency = 0 + self.total_wakeups = 0 + self.unhandled: Dict[str, int] = defaultdict(int) + self.session: Optional[perf.session] = None + + def process_event(self, sample: perf.sample_event) -> None: + """Process events.""" + event_name = str(sample.evsel) + sample_time = sample.sample_time + cpu = sample.sample_cpu + + if "sched:sched_wakeup" in event_name: + try: + target_cpu = sample.target_cpu + self.last_wakeup[target_cpu] = sample_time + except AttributeError: + pass + elif "sched:sched_switch" in event_name: + wakeup_ts = self.last_wakeup[cpu] + if wakeup_ts: + latency = sample_time - wakeup_ts + self.max_wakeup_latency = max(self.max_wakeup_latency, latency) + self.min_wakeup_latency = min(self.min_wakeup_latency, latency) + self.total_wakeup_latency += latency + self.total_wakeups += 1 + self.last_wakeup[cpu] = 0 + else: + self.unhandled[event_name] += 1 + + def print_totals(self) -> None: + """Print summary statistics.""" + print("wakeup_latency stats:\n") + print(f"total_wakeups: {self.total_wakeups}") + if self.total_wakeups: + avg = self.total_wakeup_latency // self.total_wakeups + print(f"avg_wakeup_latency (ns): {avg}") + else: + print("avg_wakeup_latency (ns): N/A") + print(f"min_wakeup_latency (ns): {self.min_wakeup_latency}") + print(f"max_wakeup_latency (ns): {self.max_wakeup_latency}") + + if self.unhandled: + print("\nunhandled events:\n") + print(f"{'event':<40s} {'count':>10s}") + print(f"{'-'*40} {'-'*10}") + for event_name, count in self.unhandled.items(): + print(f"{event_name:<40s} {count:10d}") + + def run(self, input_file: str) -> None: + """Run the session.""" + self.session = perf.session(perf.data(input_file), sample=self.process_event) + self.session.process_events() + self.print_totals() + +def main() -> None: + """Main function.""" + parser = argparse.ArgumentParser(description="Trace wakeup latency") + parser.add_argument("-i", "--input", default="perf.data", help="Input file") + args = parser.parse_args() + + analyzer = WakeupLatency() + try: + analyzer.run(args.input) + except IOError as e: + print(e, file=sys.stderr) + sys.exit(1) + +if __name__ == "__main__": + main() -- 2.54.0.rc1.513.gad8abe7a5a-goog