[PATCH v8 33/58] perf check-perf-trace: Port check-perf-trace to use python module
From: Ian Rogers <irogers@google.com>
Date: 2026-04-28 07:20:26
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
Add a port of the check-perf-trace script that uses the perf python module directly. This approach is significantly faster than using perf script callbacks as it avoids creating intermediate dictionaries for all event fields. Assisted-by: Gemini:gemini-3.1-pro-preview Signed-off-by: Ian Rogers <irogers@google.com> --- v2: 1. String Match Accuracy: Replaced the substring check for `irq:softirq_entry` events with a robust exact string match. v3: 1. Safe Thread Resolution: Swapped out sample.sample_pid with sample.sample_tid and safeguarded the session process lookup with a try-except block. v4: 1. Git Fixup Cleanup: Squashed the lingering fixup commit from the previous session into its proper patch. v8: - Wrapped session.find_thread in a try-except block to prevent crashing on untracked PIDs. --- tools/perf/python/check-perf-trace.py | 120 ++++++++++++++++++++++++++ 1 file changed, 120 insertions(+) create mode 100755 tools/perf/python/check-perf-trace.py
diff --git a/tools/perf/python/check-perf-trace.py b/tools/perf/python/check-perf-trace.py
new file mode 100755
index 000000000000..bbcd0c520745
--- /dev/null
+++ b/tools/perf/python/check-perf-trace.py@@ -0,0 +1,120 @@ +#!/usr/bin/env python3 +# SPDX-License-Identifier: GPL-2.0 +""" +Basic test of Python scripting support for perf. +Ported from tools/perf/scripts/python/check-perf-trace.py +""" + +import argparse +import collections +import perf + +unhandled: collections.defaultdict[str, int] = collections.defaultdict(int) +session = None + +softirq_vecs = { + 0: "HI_SOFTIRQ", + 1: "TIMER_SOFTIRQ", + 2: "NET_TX_SOFTIRQ", + 3: "NET_RX_SOFTIRQ", + 4: "BLOCK_SOFTIRQ", + 5: "IRQ_POLL_SOFTIRQ", + 6: "TASKLET_SOFTIRQ", + 7: "SCHED_SOFTIRQ", + 8: "HRTIMER_SOFTIRQ", + 9: "RCU_SOFTIRQ", +} + +def trace_begin() -> None: + """Called at the start of trace processing.""" + print("trace_begin") + +def trace_end() -> None: + """Called at the end of trace processing.""" + print_unhandled() + +def symbol_str(event_name: str, field_name: str, value: int) -> str: + """Resolves symbol values to strings.""" + if event_name == "irq__softirq_entry" and field_name == "vec": + return softirq_vecs.get(value, str(value)) + return str(value) + +def flag_str(event_name: str, field_name: str, value: int) -> str: + """Resolves flag values to strings.""" + if event_name == "kmem__kmalloc" and field_name == "gfp_flags": + return f"0x{value:x}" + return str(value) + +def print_header(event_name: str, sample: perf.sample_event) -> None: + """Prints common header for events.""" + secs = sample.sample_time // 1000000000 + nsecs = sample.sample_time % 1000000000 + comm = "[unknown]" + try: + if session: + thread = session.find_thread(sample.sample_pid) + if thread: + comm = thread.comm() + except (TypeError, AttributeError): + pass + print(f"{event_name:<20} {sample.sample_cpu:5} {secs:05}.{nsecs:09} " + f"{sample.sample_pid:8} {comm:<20} ", end=' ') + +def print_uncommon(sample: perf.sample_event) -> None: + """Prints uncommon fields for tracepoints.""" + # Fallback to 0 if field not found (e.g. on older kernels or if not tracepoint) + pc = getattr(sample, "common_preempt_count", 0) + flags = getattr(sample, "common_flags", 0) + lock_depth = getattr(sample, "common_lock_depth", 0) + + print(f"common_preempt_count={pc}, common_flags={flags}, " + f"common_lock_depth={lock_depth}, ") + +def irq__softirq_entry(sample: perf.sample_event) -> None: + """Handles irq:softirq_entry events.""" + print_header("irq__softirq_entry", sample) + print_uncommon(sample) + print(f"vec={symbol_str('irq__softirq_entry', 'vec', sample.vec)}") + +def kmem__kmalloc(sample: perf.sample_event) -> None: + """Handles kmem:kmalloc events.""" + print_header("kmem__kmalloc", sample) + print_uncommon(sample) + + print(f"call_site={sample.call_site:d}, ptr={sample.ptr:d}, " + f"bytes_req={sample.bytes_req:d}, bytes_alloc={sample.bytes_alloc:d}, " + f"gfp_flags={flag_str('kmem__kmalloc', 'gfp_flags', sample.gfp_flags)}") + +def trace_unhandled(event_name: str) -> None: + """Tracks unhandled events.""" + unhandled[event_name] += 1 + +def print_unhandled() -> None: + """Prints summary of unhandled events.""" + if not unhandled: + return + print("\nunhandled events:\n") + print(f"{'event':<40} {'count':>10}") + print("---------------------------------------- -----------") + for event_name, count in unhandled.items(): + print(f"{event_name:<40} {count:10}") + +def process_event(sample: perf.sample_event) -> None: + """Callback for processing events.""" + event_name = str(sample.evsel) + if event_name == "evsel(irq:softirq_entry)": + irq__softirq_entry(sample) + elif "evsel(kmem:kmalloc)" in event_name: + kmem__kmalloc(sample) + else: + trace_unhandled(event_name) + +if __name__ == "__main__": + ap = argparse.ArgumentParser() + ap.add_argument("-i", "--input", default="perf.data", help="Input file name") + args = ap.parse_args() + + trace_begin() + session = perf.session(perf.data(args.input), sample=process_event) + session.process_events() + trace_end()
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2.54.0.545.g6539524ca2-goog