[PATCH v6 52/59] perf test: Migrate Intel PT virtual LBR test to use Python API
From: Ian Rogers <irogers@google.com>
Date: 2026-04-25 17:50:46
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
The Intel PT virtual LBR test used an ad-hoc Python script written on the fly to parse branch stacks. This change migrates it to use the newly added `brstack` iterator API in the `perf` Python module. Assisted-by: Gemini:gemini-3.1-pro-preview Signed-off-by: Ian Rogers <irogers@google.com> --- .../perf/tests/shell/lib/perf_brstack_max.py | 43 +++++++++++++++++++ tools/perf/tests/shell/test_intel_pt.sh | 35 +++++---------- 2 files changed, 53 insertions(+), 25 deletions(-) create mode 100644 tools/perf/tests/shell/lib/perf_brstack_max.py
diff --git a/tools/perf/tests/shell/lib/perf_brstack_max.py b/tools/perf/tests/shell/lib/perf_brstack_max.py
new file mode 100644
index 000000000000..c826e14160d6
--- /dev/null
+++ b/tools/perf/tests/shell/lib/perf_brstack_max.py@@ -0,0 +1,43 @@ +#!/usr/bin/python +# SPDX-License-Identifier: GPL-2.0 +# Determine the maximum size of branch stacks in a perf.data file. + +import argparse +import sys + +import os + +script_dir = os.path.dirname(os.path.abspath(__file__)) +python_dir = os.path.abspath(os.path.join(script_dir, "../../../python")) +sys.path.insert(0, python_dir) + +import perf + +def main(): + ap = argparse.ArgumentParser() + ap.add_argument("-i", "--input", default="perf.data", help="Input file name") + args = ap.parse_args() + + bmax = 0 + + def process_event(sample): + nonlocal bmax + try: + brstack = sample.brstack + if brstack: + n = sum(1 for _ in brstack) + if n > bmax: + bmax = n + except AttributeError: + pass + + try: + session = perf.session(perf.data(args.input), sample=process_event) + session.process_events() + print("max brstack", bmax) + except Exception as e: + print(f"Error processing events: {e}", file=sys.stderr) + sys.exit(1) + +if __name__ == "__main__": + main()
diff --git a/tools/perf/tests/shell/test_intel_pt.sh b/tools/perf/tests/shell/test_intel_pt.sh
index 8ee761f03c38..d711ecdf5be0 100755
--- a/tools/perf/tests/shell/test_intel_pt.sh
+++ b/tools/perf/tests/shell/test_intel_pt.sh@@ -24,7 +24,6 @@ errfile="${temp_dir}/test-err.txt" workload="${temp_dir}/workload" awkscript="${temp_dir}/awkscript" jitdump_workload="${temp_dir}/jitdump_workload" -maxbrstack="${temp_dir}/maxbrstack.py" cleanup() {
@@ -539,34 +538,20 @@ test_kernel_trace() test_virtual_lbr() { echo "--- Test virtual LBR ---" - # Check if python script is supported - libpython=$(perf version --build-options | grep python | grep -cv OFF) - if [ "${libpython}" != "1" ] ; then - echo "SKIP: python scripting is not supported" + # shellcheck source=lib/setup_python.sh + . "$(dirname "$0")"/lib/setup_python.sh + + if [ -z "$PYTHON" ] ; then + echo "SKIP: Python not found" return 2 fi - # Python script to determine the maximum size of branch stacks - cat << "_end_of_file_" > "${maxbrstack}" -from __future__ import print_function - -bmax = 0 - -def process_event(param_dict): - if "brstack" in param_dict: - brstack = param_dict["brstack"] - n = len(brstack) - global bmax - if n > bmax: - bmax = n - -def trace_end(): - print("max brstack", bmax) -_end_of_file_ - # Check if virtual lbr is working - perf_record_no_bpf -o "${perfdatafile}" --aux-sample -e '{intel_pt//,cycles}:u' uname - times_val=$(perf script -i "${perfdatafile}" --itrace=L -s "${maxbrstack}" 2>/dev/null | grep "max brstack " | cut -d " " -f 3) + perf_record_no_bpf -o "${tmpfile}" --aux-sample -e '{intel_pt//,cycles}:u' perf test -w brstack + perf inject --itrace=L -i "${tmpfile}" -o "${perfdatafile}" + output=$($PYTHON "$(dirname "$0")"/lib/perf_brstack_max.py -i "${perfdatafile}") + echo "Debug: perf_brstack_max.py output: $output" + times_val=$(echo "$output" | grep "max brstack " | cut -d " " -f 3) case "${times_val}" in [0-9]*) ;; *) times_val=0;;
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2.54.0.545.g6539524ca2-goog