linux-kernel - Re: [PATCH 3/3] perf test: Add kernel lock contention test

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <7c89e623-c90f-181b-d22a-e1349ddb3340@intel.com>
Date:   Sat, 24 Sep 2022 11:09:58 +0300
From:   Adrian Hunter <adrian.hunter@...el.com>
To:     Namhyung Kim <namhyung@...nel.org>,
        Arnaldo Carvalho de Melo <acme@...nel.org>,
        Jiri Olsa <jolsa@...nel.org>
Cc:     Ingo Molnar <mingo@...nel.org>,
        Peter Zijlstra <peterz@...radead.org>,
        LKML <linux-kernel@...r.kernel.org>,
        Ian Rogers <irogers@...gle.com>,
        linux-perf-users@...r.kernel.org
Subject: Re: [PATCH 3/3] perf test: Add kernel lock contention test

On 24/09/22 03:42, Namhyung Kim wrote:
> Add a new shell test to check if both normal perf lock record +
> contention and BPF (with -b) option are working.  Use perf bench
> sched messaging as a workload since it'd create some contention for
> sending and receiving messages.
> 
> Signed-off-by: Namhyung Kim <namhyung@...nel.org>

There are a few things below that don't need to be fixed but
are perhaps things to be aware of.

Nevertheless:

Acked-by: Adrian Hunter <adrian.hunter@...el.com>


> ---
>  tools/perf/tests/shell/lock_contention.sh | 73 +++++++++++++++++++++++
>  1 file changed, 73 insertions(+)
>  create mode 100755 tools/perf/tests/shell/lock_contention.sh
> 
> diff --git a/tools/perf/tests/shell/lock_contention.sh b/tools/perf/tests/shell/lock_contention.sh
> new file mode 100755
> index 000000000000..04bf604e3c6f
> --- /dev/null
> +++ b/tools/perf/tests/shell/lock_contention.sh
> @@ -0,0 +1,73 @@
> +#!/bin/sh
> +# kernel lock contention analysis test
> +# SPDX-License-Identifier: GPL-2.0

All the shell tests are like this, but checkpatch says:

WARNING: Missing or malformed SPDX-License-Identifier tag in line 2
#24: FILE: tools/perf/tests/shell/lock_contention.sh:2:
+# kernel lock contention analysis test

WARNING: Misplaced SPDX-License-Identifier tag - use line 2 instead
#25: FILE: tools/perf/tests/shell/lock_contention.sh:3:
+# 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)
> +
> +cleanup() {
> +	rm -f ${perfdata}
> +	rm -f ${result}
> +	trap - exit term int
> +}
> +
> +trap_cleanup() {
> +	cleanup

With "set -e", a command failure will end up here with err=0

> +	exit ${err}
> +}
> +trap trap_cleanup exit term int

shellcheck -S warning tools/perf/tests/shell/lock_contention.sh

In tools/perf/tests/shell/lock_contention.sh line 14:
        trap - exit term int
               ^--^ SC2039: In POSIX sh, using lower/mixed case for signal names is undefined.
                    ^--^ SC2039: In POSIX sh, using lower/mixed case for signal names is undefined.
                         ^-^ SC2039: In POSIX sh, using lower/mixed case for signal names is undefined.


In tools/perf/tests/shell/lock_contention.sh line 21:
trap trap_cleanup exit term int
                  ^--^ SC2039: In POSIX sh, using lower/mixed case for signal names is undefined.
                       ^--^ SC2039: In POSIX sh, using lower/mixed case for signal names is undefined.
                            ^-^ SC2039: In POSIX sh, using lower/mixed case for signal names is undefined.


> +
> +check() {
> +	if [ `id -u` != 0 ]; then
> +		echo "[Skip] No root permission"
> +		err=2
> +		exit
> +	fi
> +
> +	if ! perf list | grep -q lock:contention_begin; then
> +		echo "[Skip] No lock contention tracepoints"
> +		err=2
> +		exit
> +	fi
> +}
> +
> +test_record()
> +{
> +	echo "Testing perf lock record and perf lock contention"
> +	perf lock record -o ${perfdata} -- perf bench sched messaging > /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"
> +		exit
> +	fi
> +
> +	# the perf lock contention output goes to the stderr
> +	perf lock con -a -b -E 1 -q -- perf bench sched messaging > /dev/null 2> ${result}
> +	if [ $(cat "${result}" | wc -l) != "1" ]; then
> +		echo "[Fail] BPF result count is not 1:" $(cat "${result}" | wc -l)
> +		err=1
> +		exit
> +	fi
> +}
> +
> +check
> +
> +test_record
> +test_bpf
> +
> +exit ${err}