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Date: Tue, 13 Sep 2022 10:37:50 -0700
From: Namhyung Kim <namhyung@...nel.org>
To: Adrian Hunter <adrian.hunter@...el.com>
Cc: Arnaldo Carvalho de Melo <acme@...nel.org>,
Jiri Olsa <jolsa@...hat.com>, Ian Rogers <irogers@...gle.com>,
linux-kernel <linux-kernel@...r.kernel.org>,
linux-perf-users <linux-perf-users@...r.kernel.org>
Subject: Re: [PATCH 11/11] perf test: test_intel_pt.sh: Add per-thread test
On Mon, Sep 12, 2022 at 1:34 AM Adrian Hunter <adrian.hunter@...el.com> wrote:
>
> When tracing the kernel with Intel PT, text_poke events are recorded
> per-cpu. In per-thread mode that results in a mixture of per-thread and
> per-cpu events and mmaps. Check that happens correctly.
>
> The debug output from perf record -vvv is recorded and then awk used to
> process the debug messages that indicate what file descriptors were opened
> and whether they were mmapped or set-output.
>
> Signed-off-by: Adrian Hunter <adrian.hunter@...el.com>
> ---
> tools/perf/tests/shell/test_intel_pt.sh | 247 ++++++++++++++++++++++++
> 1 file changed, 247 insertions(+)
>
> diff --git a/tools/perf/tests/shell/test_intel_pt.sh b/tools/perf/tests/shell/test_intel_pt.sh
> index 2d489de9097b..051d088c1b74 100755
> --- a/tools/perf/tests/shell/test_intel_pt.sh
> +++ b/tools/perf/tests/shell/test_intel_pt.sh
> @@ -4,6 +4,8 @@
>
> set -e
>
> +tenths=date\ +%s%1N
> +
> # Skip if no Intel PT
> perf list | grep -q 'intel_pt//' || exit 2
>
> @@ -15,6 +17,10 @@ temp_dir=$(mktemp -d /tmp/perf-test-intel-pt-sh.XXXXXXXXXX)
>
> tmpfile="${temp_dir}/tmp-perf.data"
> perfdatafile="${temp_dir}/test-perf.data"
> +outfile="${temp_dir}/test-out.txt"
> +errfile="${temp_dir}/test-err.txt"
> +workload="${temp_dir}/workload"
> +awkscript="${temp_dir}/awkscript"
>
> cleanup()
> {
> @@ -35,6 +41,37 @@ trap_cleanup()
>
> trap trap_cleanup EXIT TERM INT
>
> +have_workload=false
> +cat << _end_of_file_ | /usr/bin/cc -o "${workload}" -xc - -pthread && have_workload=true
> +#include <time.h>
> +#include <pthread.h>
> +
> +void work(void) {
> + struct timespec tm = {
> + .tv_nsec = 1000000,
> + };
> + int i;
> +
> + /* Run for about 30 seconds */
> + for (i = 0; i < 30000; i++)
> + nanosleep(&tm, NULL);
> +}
> +
> +void *threadfunc(void *arg) {
> + work();
> + return NULL;
> +}
> +
> +int main(void) {
> + pthread_t th;
> +
> + pthread_create(&th, NULL, threadfunc, NULL);
> + work();
> + pthread_join(th, NULL);
> + return 0;
> +}
> +_end_of_file_
> +
> can_cpu_wide()
> {
> echo "Checking for CPU-wide recording on CPU $1"
> @@ -69,6 +106,214 @@ test_system_wide_side_band()
> return 1
> }
>
> +can_kernel()
> +{
> + perf record -o "${tmpfile}" -B -N --no-bpf-event -e dummy:k true >/dev/null 2>&1 || return 2
> + return 0
> +}
> +
> +wait_for_threads()
> +{
> + start_time=$($tenths)
> + while [ -e "/proc/$1/task" ] ; do
> + th_cnt=$(find "/proc/$1/task" -mindepth 1 -maxdepth 1 -printf x | wc -c)
> + if [ "${th_cnt}" -ge "$2" ] ; then
> + return 0
> + fi
> + # Wait at most 5 seconds
> + if [ $(($($tenths) - start_time)) -ge 50 ] ; then
It's a shame that we would use this syntax but I couldn't find any better. :(
> + echo "PID $1 does not have $2 threads"
> + return 1
> + fi
> + done
> + return 1
> +}
> +
> +wait_for_perf_to_start()
> +{
> + echo "Waiting for \"perf record has started\" message"
> + start_time=$($tenths)
> + while [ -e "/proc/$1" ] ; do
> + if grep -q "perf record has started" "${errfile}" ; then
> + echo OK
> + break
> + fi
> + # Wait at most 5 seconds
> + if [ $(($($tenths) - start_time)) -ge 50 ] ; then
> + echo "perf recording did not start"
> + return 1
> + fi
> + done
> + return 0
> +}
> +
> +wait_for_process_to_exit()
> +{
> + start_time=$($tenths)
> + while [ -e "/proc/$1" ] ; do
> + # Wait at most 5 seconds
> + if [ $(($($tenths) - start_time)) -ge 50 ] ; then
> + echo "PID $1 did not exit as expected"
> + return 1
> + fi
> + done
> + return 0
> +}
> +
> +is_running()
> +{
> + start_time=$($tenths)
> + while [ -e "/proc/$1" ] ; do
> + # Check for at least 0.3s
> + if [ $(($($tenths) - start_time)) -gt 3 ] ; then
> + return 0
> + fi
> + done
> + echo "PID $1 exited prematurely"
> + return 1
> +}
Can we move this into the lib directory with an optional argument
specifying the timeout?
Thanks,
Namhyung
> +
> +test_per_thread()
> +{
> + k="$1"
> + desc="$2"
> +
> + echo "--- Test per-thread ${desc}recording ---"
> +
> + if ! $have_workload ; then
> + echo "No workload, so skipping"
> + return 2
> + fi
> +
> + if [ "${k}" = "k" ] ; then
> + can_kernel || return 2
> + fi
> +
> + cat <<- "_end_of_file_" > "${awkscript}"
> + BEGIN {
> + s = "[ ]*"
> + u = s"[0-9]+"s
> + d = s"[0-9-]+"s
> + x = s"[0-9a-fA-FxX]+"s
> + mmapping = "idx"u": mmapping fd"u
> + set_output = "idx"u": set output fd"u"->"u
> + perf_event_open = "sys_perf_event_open: pid"d"cpu"d"group_fd"d"flags"x"="u
> + }
> +
> + /perf record opening and mmapping events/ {
> + if (!done)
> + active = 1
> + }
> +
> + /perf record done opening and mmapping events/ {
> + active = 0
> + done = 1
> + }
> +
> + $0 ~ perf_event_open && active {
> + match($0, perf_event_open)
> + $0 = substr($0, RSTART, RLENGTH)
> + pid = $3
> + cpu = $5
> + fd = $11
> + print "pid " pid " cpu " cpu " fd " fd " : " $0
> + fd_array[fd] = fd
> + pid_array[fd] = pid
> + cpu_array[fd] = cpu
> + }
> +
> + $0 ~ mmapping && active {
> + match($0, mmapping)
> + $0 = substr($0, RSTART, RLENGTH)
> + fd = $5
> + print "fd " fd " : " $0
> + if (fd in fd_array) {
> + mmap_array[fd] = 1
> + } else {
> + print "Unknown fd " fd
> + exit 1
> + }
> + }
> +
> + $0 ~ set_output && active {
> + match($0, set_output)
> + $0 = substr($0, RSTART, RLENGTH)
> + fd = $6
> + fd_to = $8
> + print "fd " fd " fd_to " fd_to " : " $0
> + if (fd in fd_array) {
> + if (fd_to in fd_array) {
> + set_output_array[fd] = fd_to
> + } else {
> + print "Unknown fd " fd_to
> + exit 1
> + }
> + } else {
> + print "Unknown fd " fd
> + exit 1
> + }
> + }
> +
> + END {
> + print "Checking " length(fd_array) " fds"
> + for (fd in fd_array) {
> + if (fd in mmap_array) {
> + pid = pid_array[fd]
> + if (pid != -1) {
> + if (pid in pids) {
> + print "More than 1 mmap for PID " pid
> + exit 1
> + }
> + pids[pid] = 1
> + }
> + cpu = cpu_array[fd]
> + if (cpu != -1) {
> + if (cpu in cpus) {
> + print "More than 1 mmap for CPU " cpu
> + exit 1
> + }
> + cpus[cpu] = 1
> + }
> + } else if (!(fd in set_output_array)) {
> + print "No mmap for fd " fd
> + exit 1
> + }
> + }
> + n = length(pids)
> + if (n != thread_cnt) {
> + print "Expected " thread_cnt " per-thread mmaps - found " n
> + exit 1
> + }
> + }
> + _end_of_file_
> +
> + $workload &
> + w1=$!
> + $workload &
> + w2=$!
> + echo "Workload PIDs are $w1 and $w2"
> + wait_for_threads ${w1} 2
> + wait_for_threads ${w2} 2
> +
> + perf record -B -N --no-bpf-event -o "${perfdatafile}" -e intel_pt//u"${k}" -vvv --per-thread -p "${w1},${w2}" 2>"${errfile}" >"${outfile}" &
> + ppid=$!
> + echo "perf PID is $ppid"
> + wait_for_perf_to_start ${ppid} || return 1
> +
> + kill ${w1}
> + wait_for_process_to_exit ${w1} || return 1
> + is_running ${ppid} || return 1
> +
> + kill ${w2}
> + wait_for_process_to_exit ${w2} || return 1
> + wait_for_process_to_exit ${ppid} || return 1
> +
> + awk -v thread_cnt=4 -f "${awkscript}" "${errfile}" || return 1
> +
> + echo OK
> + return 0
> +}
> +
> count_result()
> {
> if [ "$1" -eq 2 ] ; then
> @@ -85,6 +330,8 @@ count_result()
>
> ret=0
> test_system_wide_side_band || ret=$? ; count_result $ret
> +test_per_thread "" "" || ret=$? ; count_result $ret
> +test_per_thread "k" "(incl. kernel) " || ret=$? ; count_result $ret
>
> cleanup
>
> --
> 2.25.1
>
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