tools/perf/tests/shell/lock_contention.sh

Source file repositories/reference/linux-study-clean/tools/perf/tests/shell/lock_contention.sh

File Facts

System
Linux kernel
Corpus path
tools/perf/tests/shell/lock_contention.sh
Extension
.sh
Size
9392 bytes
Lines
346
Domain
Support Tooling And Documentation
Bucket
tools
Inferred role
Support Tooling And Documentation: tools
Status
atlas-only

Why This File Exists

Repository support layer: documentation, build tooling, samples, user-space helper tools, generated initramfs support, licenses, and validation utilities.

Dependency Surface

Detected Declarations

Annotated Snippet

#!/bin/bash
# kernel lock contention analysis test
# SPDX-License-Identifier: GPL-2.0

set -e

err=0
perfdata=$(mktemp /tmp/__perf_test.perf.data.XXXXX)
result=$(mktemp /tmp/__perf_test.result.XXXXX)
errout=$(mktemp /tmp/__perf_test.errout.XXXXX)

cleanup() {
	rm -f ${perfdata}
	rm -f ${result}
	rm -f ${errout}
	trap - EXIT TERM INT ERR
}

trap_cleanup() {
	if (( $? == 139 )); then #SIGSEGV
		err=1
	fi
	echo "Unexpected signal in ${FUNCNAME[1]}"
	cleanup
	exit ${err}
}
trap trap_cleanup EXIT TERM INT ERR

check() {
	if [ "$(id -u)" != 0 ]; then
		echo "[Skip] No root permission"
		err=2
		exit
	fi

	if ! perf list tracepoint | grep -q lock:contention_begin; then
		echo "[Skip] No lock contention tracepoints"
		err=2
		exit
	fi

	# shellcheck disable=SC2046
	if [ `nproc` -lt 4 ]; then
		echo "[Skip] Low number of CPUs (`nproc`), lock event cannot be triggered certainly"
		err=2
		exit
	fi
}

test_record()
{
	echo "Testing perf lock record and perf lock contention"
	perf lock record -o ${perfdata} -- perf bench sched messaging -p > /dev/null 2>&1
	# the output goes to the stderr and we expect only 1 output (-E 1)
	perf lock contention -i ${perfdata} -E 1 -q 2> ${result}
	if [ "$(cat "${result}" | wc -l)" != "1" ]; then
		echo "[Fail] Recorded result count is not 1:" "$(cat "${result}" | wc -l)"
		err=1
		exit
	fi
}

test_bpf()
{
	echo "Testing perf lock contention --use-bpf"

	if ! perf lock con -b true > /dev/null 2>&1 ; then
		echo "[Skip] No BPF support"
		return
	fi

Annotation

Implementation Notes