#!/bin/sh# SPDX-License-Identifier: GPL-2.0# Test libdw unwinding of multi-threaded processes (exclusive) set -e if ! perf check feature -q libdw-dwarf-unwind; then	echo "Skip: libdw DWARF unwinding is not available"	exit 2fi tmpdir=$(mktemp -d /tmp/perf-test-dwarf-unwind-multithreaded.XXXXXX)perf_data="$tmpdir/perf.data"perf_script="$tmpdir/perf-script.txt"nr_threads=4nr_worker_threads=$((nr_threads - 1)) cleanup(){	trap - EXIT TERM INT	rm -rf "$tmpdir"} trap cleanup EXIT TERM INT if ! perf record -q -e task-clock:u -F 99 --call-graph dwarf,8192 \	-o "$perf_data" -- perf test -w thloop 2 "$nr_threads"then	echo "Skip: failed to record task-clock:u"	exit 2fi if ! perf script --unwind-style=libdw \	-F comm,pid,tid,event,ip,sym -i "$perf_data" > "$perf_script"then	echo "Error: failed to process the recording with libdw" >&2	exit 1fi nr_unwound_threads=$(	awk '		BEGIN { RS = "" } 		# thfunc is the worker-only caller of test_loop. Finding it proves		# that libdw unwound beyond the sampled leaf for this worker TID.		/thfunc/ {			split($2, id, "/")			seen[id[2]] = 1		} 		END {			for (tid in seen)				nr_tids++			print nr_tids + 0		}	' "$perf_script") if [ "$nr_unwound_threads" -ne "$nr_worker_threads" ]; then	echo "Error: expected callchains for $nr_worker_threads worker TIDs," \		"found $nr_unwound_threads" >&2	exit 1fi exit 0