[PATCH v3 06/13] perf tests: Fix Python JIT dump profiling test failure

[Ian Rogers]

The `python profiling with jitdump` test failed due to:
1. Target PID extraction resolving to duplicate space-separated values,
   which broke the buildid-cache loops.
2. The default workload duration being too short to capture JIT stack
   trampoline samples, resulting in 0 matching JIT symbols.

Fix the PID parsing by sorting and retrieving a unique single-line value.
Implement a robust retry loop starting at 1M python loop iterations and
scaling up to 100M iterations until JIT symbols are successfully captured
and verified.

Fixes: c9cd0c7e529e ("perf test: Add python JIT dump test")
Assisted-by: Antigravity:gemini-3.1-pro
Signed-off-by: Ian Rogers <irogers@xxxxxxxxxx>
---
 tools/perf/tests/shell/jitdump-python.sh | 79 ++++++++++++++++--------
 1 file changed, 53 insertions(+), 26 deletions(-)

diff --git a/tools/perf/tests/shell/jitdump-python.sh b/tools/perf/tests/shell/jitdump-python.sh
index ae86203b14a2..05aaa3bd900b 100755
--- a/tools/perf/tests/shell/jitdump-python.sh
+++ b/tools/perf/tests/shell/jitdump-python.sh
@@ -16,11 +16,15 @@ if [ "${HAS_PERF_JIT}" != "True" ]; then
     exit 2
 fi
 
-PERF_DATA=$(mktemp /tmp/__perf_test.perf.data.XXXXXX)
+PERF_DATA_DIR=$(mktemp -d /tmp/__perf_test.perf.data.dir.XXXXXX)
+PERF_DATA="${PERF_DATA_DIR}/perf.data"
 
 cleanup() {
     echo "Cleaning up files..."
-    rm -f ${PERF_DATA} ${PERF_DATA}.jit /tmp/jit-${PID}.dump /tmp/jitted-${PID}-*.so 2> /dev/null
+    rm -rf ${PERF_DATA_DIR} 2> /dev/null
+    for p in ${ALL_PIDS}; do
+        rm -f /tmp/jit-${p}.dump /tmp/jitted-${p}-*.so 2> /dev/null
+    done
 
     trap - EXIT TERM INT
 }
@@ -33,9 +37,16 @@ trap_cleanup() {
 
 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
+ALL_PIDS=""
+NUM=0
+for iterations in 1000000 10000000 50000000 100000000; do
+    echo "Running with $iterations iterations..."
+    rm -f "${PERF_DATA}.pid"
+    cat <<EOF | perf record -k 1 -g --call-graph dwarf -o "${PERF_DATA}" -- ${PYTHON} -Xperf_jit
+import os
+with open("${PERF_DATA}.pid", "w") as f:
+    f.write(str(os.getpid()))
+
 def foo(n):
     result = 0
     for _ in range(n):
@@ -49,29 +60,45 @@ def baz(n):
     bar(n)
 
 if __name__ == "__main__":
-    baz(1000000)
+    baz($iterations)
 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 "${F}"
+    if [ -f "${PERF_DATA}.pid" ]; then
+        REAL_PID=$(cat "${PERF_DATA}.pid")
+        ALL_PIDS="${ALL_PIDS} ${REAL_PID}"
+    fi
+
+    # extract PID of the target process from the data
+    PID=$(perf report -i "${PERF_DATA}" --stdio -F pid -q -g none | \
+          cut -d: -f1 -s | sort -u | head -n 1 | tr -d ' ')
+    if [ -z "${PID}" ]; then
+        echo "Failed to get PID, retrying..."
+        continue
+    fi
+    ALL_PIDS="${ALL_PIDS} ${PID}"
+
+    echo "Generate JIT-ed DSOs using perf inject"
+    DEBUGINFOD_URLS='' perf inject -i "${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 "${PERF_DATA}.jit" -s sym --stdio | grep -cE 'py::(foo|bar|baz):<stdin>')
+
+    echo "Remove JIT-ed DSOs from the build-ID cache"
+    for F in /tmp/jitted-${PID}-*.so; do
+        perf buildid-cache -r "${F}"
+    done
+    rm -f /tmp/jitted-${PID}-*.so /tmp/jit-${PID}.dump 2>/dev/null
+
+    if [ "${NUM}" -gt 0 ]; then
+        echo "Success: found ${NUM} matching lines"
+        break
+    fi
+    echo "No matching lines found, retrying with more iterations..."
 done
 
 cleanup
-- 
2.54.0.1189.g8c84645362-goog