Messages in this thread | | | Subject | Re: [PATCH v4] perf test: Introduce script for Arm CoreSight testing | From | Suzuki K Poulose <> | Date | Wed, 12 Aug 2020 17:59:55 +0100 |
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Hi Leo,
On 08/06/2020 08:02 AM, Leo Yan wrote: > We need a simple method to test Perf with Arm CoreSight drivers, this > could be used for smoke testing when new patch is coming for perf or > CoreSight drivers, and we also can use the test to confirm if the > CoreSight has been enabled successfully on new platforms. > > This patch introduces the shell script test_arm_coresight.sh which is > under the 'pert test' framework. This script provides three testing > scenarios:
Thank you for this testcase. It is a very good tool for people check their system for CoreSight driver functionality.
> > Test scenario 1: traverse all possible paths between source and sink > > For traversing possible paths, simply to say, the testing rationale > is source oriented testing, it traverses every source (now only refers > to ETM device) and test its all possible sinks. To search the complete > paths from one specific source to its sinks, this patch relies on the > sysfs '/sys/bus/coresight/devices/devX/out:Y' for depth-first search > (DFS) for iteration connected device nodes, if the output device is > detected as one of ETR, ETF, or ETB types then it will test trace data
Please see my suggestion below, to use "enable_sink" as an indicator for a sink device.
> recording and decoding for this PMU device. > > The script runs three output testings for every trace data: > - Test branch samples dumping with 'perf script' command; > - Test branch samples reporting with 'perf report' command; > - Use option '--itrace=i1000i' to insert synthesized instructions events > and the script will check if perf can output the percentage value > successfully based on the instruction samples. > > Test scenario 2: CPU wide mode test > > For CPU wide mode testing, it passes option '-a' to perf tool to enable > tracing on all CPUs, so it's hard to say which program will be traced.
Isn't this system-wide, when you trace all CPUs ? In CPU wide mode, you specify a list of CPUs (-C ?). I always get confused here.
> But perf tool itself contributes much overload in this case, so it will > parse trace data and check if process 'perf' can be detected or not. > > diff --git a/tools/perf/tests/shell/test_arm_coresight.sh b/tools/perf/tests/shell/test_arm_coresight.sh > new file mode 100755 > index 000000000000..73b973bada26 > --- /dev/null > +++ b/tools/perf/tests/shell/test_arm_coresight.sh > @@ -0,0 +1,172 @@ > +#!/bin/sh > +# Check Arm CoreSight trace data recording and branch samples > + > +# Uses the 'perf record' to record trace data with Arm CoreSight sinks; > +# then verify if there have any branch samples and instruction samples > +# are generated by CoreSight with 'perf script' and 'perf report' > +# commands. > + > +# SPDX-License-Identifier: GPL-2.0 > +# Leo Yan <leo.yan@linaro.org>, 2020 > + > +perfdata=$(mktemp /tmp/__perf_test.perf.data.XXXXX) > +file=$(mktemp /tmp/temporary_file.XXXXX) > + > +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 > + > +record_touch_file() { > + echo "Recording trace (only user mode) with path: CPU$2 => $1" > + perf record -o ${perfdata} -e cs_etm/@$1/u --per-thread \ > + -- taskset -c $2 touch $file > +} > + > +perf_script_branch_samples() { > + echo "Looking at perf.data file for dumping branch samples:" > + > + # Below is an example of the branch samples dumping: > + # touch 6512 1 branches:u: ffffb220824c strcmp+0xc (/lib/aarch64-linux-gnu/ld-2.27.so) > + # touch 6512 1 branches:u: ffffb22082e0 strcmp+0xa0 (/lib/aarch64-linux-gnu/ld-2.27.so) > + # touch 6512 1 branches:u: ffffb2208320 strcmp+0xe0 (/lib/aarch64-linux-gnu/ld-2.27.so) > + perf script -F,-time -i ${perfdata} | \ > + egrep " +$1 +[0-9]+ .* +branches:([u|k]:)? +" > +} > + > +perf_report_branch_samples() { > + echo "Looking at perf.data file for reporting branch samples:" > + > + # Below is an example of the branch samples reporting: > + # 73.04% 73.04% touch libc-2.27.so [.] _dl_addr > + # 7.71% 7.71% touch libc-2.27.so [.] getenv > + # 2.59% 2.59% touch ld-2.27.so [.] strcmp > + perf report --stdio -i ${perfdata} | \ > + egrep " +[0-9]+\.[0-9]+% +[0-9]+\.[0-9]+% +$1 " > +} > + > +perf_report_instruction_samples() { > + echo "Looking at perf.data file for instruction samples:" > + > + # Below is an example of the instruction samples reporting: > + # 68.12% touch libc-2.27.so [.] _dl_addr > + # 5.80% touch libc-2.27.so [.] getenv > + # 4.35% touch ld-2.27.so [.] _dl_fixup > + perf report --itrace=i1000i --stdio -i ${perfdata} | \ > + egrep " +[0-9]+\.[0-9]+% +$1" > +} > + > +arm_cs_iterate_devices() { > + for dev in $1/connections/out\:*; do > + > + # Skip testing if it's not a directory > + ! [ -d $dev ] && continue; > + > + # Read out its symbol link file name > + path=`readlink -f $dev` > + > + # Extract device name from path, e.g. > + # path = '/sys/devices/platform/20010000.etf/tmc_etf0' > + # `> device_name = 'tmc_etf0' > + device_name=`echo $path | awk -F/ '{print $(NF)}'` > + > + echo $device_name | egrep -q "etr|etb|etf"
Could we check for the existence of "enable_sink" instead, for detecting if this is a sink device ? That way, we are covered for future cases of a new sink type, and is more reliable.
> + > + # Only test if the output device is ETR/ETB/ETF > + if [ $? -eq 0 ]; then > + > + pmu_dev="/sys/bus/event_source/devices/cs_etm/sinks/$device_name" > + > + # Exit if PMU device node doesn't exist > + if ! [ -f $pmu_dev ]; then > + echo "PMU device $pmu_dev doesn't exist"
Misleading output. $pmu_dev is not a PMU device. Instead, it is one of the supported sinks by the PMU.
> + exit 1 > + fi > + > + record_touch_file $device_name $2 && > + perf_script_branch_samples touch && > + perf_report_branch_samples touch && > + perf_report_instruction_samples touch > + > + err=$? > + > + # Exit when find failure > + [ $err != 0 ] && exit $err > + > + rm -f ${perfdata} > + rm -f ${file} > + fi > + > + arm_cs_iterate_devices $dev $2 > + done > +} > + > +arm_cs_etm_traverse_path_test() { > + # Iterate for every ETM device > + for dev in /sys/bus/coresight/devices/etm*; do > + > + # Find the ETM device belonging to which CPU > + cpu=`cat $dev/cpu` > + > + echo $dev > + echo $cpu > + > + # Use depth-first search (DFS) to iterate outputs > + arm_cs_iterate_devices $dev $cpu > + done > +} > + > +arm_cs_etm_cpu_wide_test() { > + echo "Recording trace with CPU wide mode" > + perf record -o ${perfdata} -e cs_etm// -a -- ls > + > + perf_script_branch_samples perf && > + perf_report_branch_samples perf && > + perf_report_instruction_samples perf > + > + err=$? > + > + # Exit when find failure > + [ $err != 0 ] && exit $err > + > + rm -f ${perfdata} > + rm -f ${file} > +} > + > +arm_cs_etm_snapshot_test() { > + echo "Recording trace with snapshot mode" > + perf record -o ${perfdata} -e cs_etm// -S --per-thread \ > + -- dd if=/dev/zero of=/dev/null &
As far as I understand, --per-thread option is not needed anymore for normal tracing (irrespective of whether your application is multi-threaded or not)
> + PERFPID=$! > + > + # Wait for perf program > + sleep 1 > + > + # Send signal to snapshot trace data > + kill -USR2 $PERFPID > + > + # Stop perf program > + kill $PERFPID > + wait $PERFPID > + > + perf_script_branch_samples dd && > + perf_report_branch_samples dd && > + perf_report_instruction_samples dd > + > + err=$? > + > + # Exit when find failure > + [ $err != 0 ] && exit $err > + > + rm -f ${perfdata} > + rm -f ${file} > +} > + > +arm_cs_etm_traverse_path_test > +arm_cs_etm_cpu_wide_test > +arm_cs_etm_snapshot_test > +exit 0 >
Rest looks OK to me.
Cheers Suzuki
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