[PATCH v7 47/59] perf failed-syscalls: Port failed-syscalls to use python module
From: Ian Rogers <irogers@google.com>
Date: 2026-04-25 22:51:52
Also in:
linux-perf-users, lkml
Subsystem:
performance events subsystem, the rest · Maintainers:
Peter Zijlstra, Ingo Molnar, Arnaldo Carvalho de Melo, Namhyung Kim, Linus Torvalds
Port the legacy Perl script failed-syscalls.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, making it a standalone script that reads perf.data files. It filters for sys_exit events, checks for failed syscalls (where return value ret < 0), and aggregates counts per command name. Complications: - The script is designed for file-based processing using perf.session. - 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 <irogers@google.com> --- tools/perf/python/failed-syscalls.py | 78 ++++++++++++++++++++++++++++ 1 file changed, 78 insertions(+) create mode 100755 tools/perf/python/failed-syscalls.py
diff --git a/tools/perf/python/failed-syscalls.py b/tools/perf/python/failed-syscalls.py
new file mode 100755
index 000000000000..c3b58664eb57
--- /dev/null
+++ b/tools/perf/python/failed-syscalls.py@@ -0,0 +1,78 @@ +#!/usr/bin/env python3 +# SPDX-License-Identifier: GPL-2.0 +"""Failed system call counts.""" + +import argparse +from collections import defaultdict +import sys +from typing import Optional +import perf + +class FailedSyscalls: + """Tracks and displays failed system call totals.""" + def __init__(self, comm: Optional[str] = None) -> None: + self.failed_syscalls: dict[str, int] = defaultdict(int) + self.for_comm = comm + self.session: Optional[perf.session] = None + self.unhandled: dict[str, int] = defaultdict(int) + + def process_event(self, sample: perf.sample_event) -> None: + """Process sys_exit events.""" + event_name = str(sample.evsel) + if not event_name.startswith("evsel(syscalls:sys_exit_") and \ + not event_name.startswith("evsel(raw_syscalls:sys_exit_"): + return + + try: + ret = sample.ret + except AttributeError: + self.unhandled[event_name] += 1 + return + + if ret >= 0: + return + + pid = sample.sample_pid + assert self.session is not None + try: + comm = self.session.find_thread(pid).comm() + except Exception: # pylint: disable=broad-except + comm = "unknown" + + if self.for_comm and comm != self.for_comm: + return + + self.failed_syscalls[comm] += 1 + + def print_totals(self) -> None: + """Print summary table.""" + print("\nfailed syscalls by comm:\n") + print(f"{'comm':<20s} {'# errors':>10s}") + print(f"{'-'*20} {'-'*10}") + + for comm, val in sorted(self.failed_syscalls.items(), + key=lambda kv: (kv[1], kv[0]), reverse=True): + print(f"{comm:<20s} {val: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 failed syscalls") + parser.add_argument("comm", nargs="?", help="Filter by command name") + parser.add_argument("-i", "--input", default="perf.data", help="Input file") + args = parser.parse_args() + + analyzer = FailedSyscalls(args.comm) + try: + analyzer.run(args.input) + except IOError as e: + print(e, file=sys.stderr) + sys.exit(1) + +if __name__ == "__main__": + main()
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2.54.0.545.g6539524ca2-goog