linux-kernel - [PATCH v2 2/2] perf test: Add python JIT dump test

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Message-ID: <20251125080748.461014-2-namhyung@kernel.org>
Date: Tue, 25 Nov 2025 00:07:47 -0800
From: Namhyung Kim <namhyung@...nel.org>
To: Arnaldo Carvalho de Melo <acme@...nel.org>,
	Ian Rogers <irogers@...gle.com>,
	James Clark <james.clark@...aro.org>
Cc: Jiri Olsa <jolsa@...nel.org>,
	Adrian Hunter <adrian.hunter@...el.com>,
	Peter Zijlstra <peterz@...radead.org>,
	Ingo Molnar <mingo@...nel.org>,
	LKML <linux-kernel@...r.kernel.org>,
	linux-perf-users@...r.kernel.org,
	Pablo Galindo <pablogsal@...il.com>
Subject: [PATCH v2 2/2] perf test: Add python JIT dump test

Add a test case for the python interpreter like below so that we can
make sure it won't break again.  To validate the effect of build-ID
generation, it adds and removes the JIT'ed DSOs to/from the build-ID
cache for the test.

  $ perf test -vv jitdump
   84: python profiling with jitdump:
  --- start ---
  test child forked, pid 214316
  Run python with -Xperf_jit
  [ perf record: Woken up 5 times to write data ]
  [ perf record: Captured and wrote 1.180 MB /tmp/__perf_test.perf.data.XbqZNm (140 samples) ]
  Generate JIT-ed DSOs using perf inject
  Add JIT-ed DSOs to the build-ID cache
  Check the symbol containing the script name
  Found 108 matching lines
  Remove JIT-ed DSOs from the build-ID cache
  ---- end(0) ----
   84: python profiling with jitdump                                   : Ok

Cc: Pablo Galindo <pablogsal@...il.com>
Link: https://docs.python.org/3/howto/perf_profiling.html#how-to-work-without-frame-pointers
Signed-off-by: Namhyung Kim <namhyung@...nel.org>
---
v2 changes)
* check availability of -Xperf_jit properly  (Pablo)
* use setup_python.sh  (Ian)
* do not use a separate script file  (Ian)
* add cleanup function  (Ian)

 tools/perf/tests/shell/jitdump-python.sh | 81 ++++++++++++++++++++++++
 1 file changed, 81 insertions(+)
 create mode 100755 tools/perf/tests/shell/jitdump-python.sh

diff --git a/tools/perf/tests/shell/jitdump-python.sh b/tools/perf/tests/shell/jitdump-python.sh
new file mode 100755
index 0000000000000000..ae86203b14a22b4e
--- /dev/null
+++ b/tools/perf/tests/shell/jitdump-python.sh
@@ -0,0 +1,81 @@
+#!/bin/bash
+# python profiling with jitdump
+# SPDX-License-Identifier: GPL-2.0
+
+SHELLDIR=$(dirname $0)
+# shellcheck source=lib/setup_python.sh
+. "${SHELLDIR}"/lib/setup_python.sh
+
+OUTPUT=$(${PYTHON} -Xperf_jit -c 'import os, sys; print(os.getpid(), sys.is_stack_trampoline_active())' 2> /dev/null)
+PID=${OUTPUT% *}
+HAS_PERF_JIT=${OUTPUT#* }
+
+rm -f /tmp/jit-${PID}.dump 2> /dev/null
+if [ "${HAS_PERF_JIT}" != "True" ]; then
+    echo "SKIP: python JIT dump is not available"
+    exit 2
+fi
+
+PERF_DATA=$(mktemp /tmp/__perf_test.perf.data.XXXXXX)
+
+cleanup() {
+    echo "Cleaning up files..."
+    rm -f ${PERF_DATA} ${PERF_DATA}.jit /tmp/jit-${PID}.dump /tmp/jitted-${PID}-*.so 2> /dev/null
+
+    trap - EXIT TERM INT
+}
+
+trap_cleanup() {
+    echo "Unexpected termination"
+    cleanup
+    exit 1
+}
+
+trap trap_cleanup EXIT TERM INT
+
+echo "Run python with -Xperf_jit"
+cat <<EOF | perf record -k 1 -g --call-graph dwarf -o "${PERF_DATA}" \
+		 -- ${PYTHON} -Xperf_jit
+def foo(n):
+    result = 0
+    for _ in range(n):
+        result += 1
+    return result
+
+def bar(n):
+    foo(n)
+
+def baz(n):
+    bar(n)
+
+if __name__ == "__main__":
+    baz(1000000)
+EOF
+
+# extract PID of the target process from the data
+_PID=$(perf report -i "${PERF_DATA}" -F pid -q -g none | cut -d: -f1 -s)
+PID=$(echo -n $_PID)  # remove newlines
+
+echo "Generate JIT-ed DSOs using perf inject"
+DEBUGINFOD_URLS='' perf inject -i "${PERF_DATA}" -j -o "${PERF_DATA}.jit"
+
+echo "Add JIT-ed DSOs to the build-ID cache"
+for F in /tmp/jitted-${PID}-*.so; do
+  perf buildid-cache -a "${F}"
+done
+
+echo "Check the symbol containing the function/module name"
+NUM=$(perf report -i "${PERF_DATA}.jit" -s sym | grep -cE 'py::(foo|bar|baz):<stdin>')
+
+echo "Found ${NUM} matching lines"
+
+echo "Remove JIT-ed DSOs from the build-ID cache"
+for F in /tmp/jitted-${PID}-*.so; do
+  perf buildid-cache -r "${F}"
+done
+
+cleanup
+
+if [ "${NUM}" -eq 0 ]; then
+    exit 1
+fi
-- 
2.52.0.460.gd25c4c69ec-goog