linux-kernel - Re: [PATCH v2 7/7] perf test: cs-etm: Test Coresight disassembly script

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Message-ID: <42bfbda0-3b4a-496f-a96a-8f16d3e108f7@arm.com>
Date: Fri, 13 Sep 2024 14:35:07 +0100
From: Leo Yan <leo.yan@....com>
To: James Clark <james.clark@...aro.org>, linux-perf-users@...r.kernel.org,
 gankulkarni@...amperecomputing.com, coresight@...ts.linaro.org,
 scclevenger@...amperecomputing.com
Cc: Peter Zijlstra <peterz@...radead.org>, Ingo Molnar <mingo@...hat.com>,
 Arnaldo Carvalho de Melo <acme@...nel.org>,
 Namhyung Kim <namhyung@...nel.org>, Mark Rutland <mark.rutland@....com>,
 Alexander Shishkin <alexander.shishkin@...ux.intel.com>,
 Jiri Olsa <jolsa@...nel.org>, Ian Rogers <irogers@...gle.com>,
 Adrian Hunter <adrian.hunter@...el.com>,
 "Liang, Kan" <kan.liang@...ux.intel.com>,
 Suzuki K Poulose <suzuki.poulose@....com>, Mike Leach
 <mike.leach@...aro.org>, John Garry <john.g.garry@...cle.com>,
 Will Deacon <will@...nel.org>, Leo Yan <leo.yan@...ux.dev>,
 Ben Gainey <ben.gainey@....com>, Ruidong Tian
 <tianruidong@...ux.alibaba.com>, Benjamin Gray <bgray@...ux.ibm.com>,
 Mathieu Poirier <mathieu.poirier@...aro.org>, linux-kernel@...r.kernel.org,
 linux-arm-kernel@...ts.infradead.org
Subject: Re: [PATCH v2 7/7] perf test: cs-etm: Test Coresight disassembly
 script



On 9/12/24 16:11, James Clark wrote:
> 
> Run a few samples through the disassembly script and check to see that
> at least one branch instruction is printed.
> 
> Signed-off-by: James Clark <james.clark@...aro.org>
> ---
>   .../tests/shell/test_arm_coresight_disasm.sh  | 63 +++++++++++++++++++
>   1 file changed, 63 insertions(+)
>   create mode 100755 tools/perf/tests/shell/test_arm_coresight_disasm.sh
> 
> diff --git a/tools/perf/tests/shell/test_arm_coresight_disasm.sh b/tools/perf/tests/shell/test_arm_coresight_disasm.sh
> new file mode 100755
> index 000000000000..6d004bf29f80
> --- /dev/null
> +++ b/tools/perf/tests/shell/test_arm_coresight_disasm.sh
> @@ -0,0 +1,63 @@
> +#!/bin/sh
> +# Check Arm CoreSight disassembly script completes without errors
> +# SPDX-License-Identifier: GPL-2.0
> +
> +# The disassembly script reconstructs ranges of instructions and gives these to objdump to
> +# decode. objdump doesn't like ranges that go backwards, but these are a good indication
> +# that decoding has gone wrong either in OpenCSD, Perf or in the range reconstruction in
> +# the script. Test all 3 parts are working correctly by running the script.
> +
> +skip_if_no_cs_etm_event() {
> +       perf list | grep -q 'cs_etm//' && return 0
> +
> +       # cs_etm event doesn't exist
> +       return 2
> +}
> +
> +skip_if_no_cs_etm_event || exit 2
> +
> +# Assume an error unless we reach the very end
> +set -e
> +glb_err=1
> +
> +perfdata_dir=$(mktemp -d /tmp/__perf_test.perf.data.XXXXX)
> +perfdata=${perfdata_dir}/perf.data
> +file=$(mktemp /tmp/temporary_file.XXXXX)
> +
> +cleanup_files()
> +{
> +       set +e
> +       rm -rf ${perfdata_dir}
> +       rm -f ${file}
> +       trap - EXIT TERM INT
> +       exit $glb_err
> +}
> +
> +trap cleanup_files EXIT TERM INT
> +
> +# Ranges start and end on branches, so check for some likely branch instructions
> +sep="\s\|\s"
> +branch_search="\sbl${sep}b${sep}b.ne${sep}b.eq${sep}cbz\s"
> +
> +## Test kernel ##
> +if [ -e /proc/kcore ]; then
> +       echo "Testing kernel disassembly"
> +       perf record -o ${perfdata} -e cs_etm//k --kcore -- touch $file > /dev/null 2>&1
> +       perf script -i ${perfdata} -s python:tools/perf/scripts/python/arm-cs-trace-disasm.py -- \
> +               -d --stop-sample=30 2> /dev/null > ${file}

This is fine for self test. But for a CI test in a distro, will it fail to
find script with prefix 'tools/perf/...'?

Thanks,
Leo

> +       grep -q -e ${branch_search} ${file}
> +       echo "Found kernel branches"
> +else
> +       # kcore is required for correct kernel decode due to runtime code patching
> +       echo "No kcore, skipping kernel test"
> +fi
> +
> +## Test user ##
> +echo "Testing userspace disassembly"
> +perf record -o ${perfdata} -e cs_etm//u -- touch $file > /dev/null 2>&1
> +perf script -i ${perfdata} -s python:tools/perf/scripts/python/arm-cs-trace-disasm.py -- \
> +       -d --stop-sample=30 2> /dev/null > ${file}
> +grep -q -e ${branch_search} ${file}
> +echo "Found userspace branches"
> +
> +glb_err=0
> --
> 2.34.1
>