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Message-ID: <CAP-5=fW4QQk6fFMUyr+KFekA+sfkzsg-vKeCvaQYk0Srwsr4bQ@mail.gmail.com>
Date: Tue, 4 Mar 2025 22:07:56 -0800
From: Ian Rogers <irogers@...gle.com>
To: Dapeng Mi <dapeng1.mi@...ux.intel.com>
Cc: Peter Zijlstra <peterz@...radead.org>, Ingo Molnar <mingo@...hat.com>,
Arnaldo Carvalho de Melo <acme@...nel.org>, Namhyung Kim <namhyung@...nel.org>,
Adrian Hunter <adrian.hunter@...el.com>,
Alexander Shishkin <alexander.shishkin@...ux.intel.com>, Kan Liang <kan.liang@...ux.intel.com>,
linux-perf-users@...r.kernel.org, linux-kernel@...r.kernel.org,
Dapeng Mi <dapeng1.mi@...el.com>
Subject: Re: [PATCH 2/2] perf tools/tests: Fix topdown groups test on hybrid platforms
On Sun, Feb 23, 2025 at 5:43 PM Dapeng Mi <dapeng1.mi@...ux.intel.com> wrote:
>
> When running topdown groups test on hybrid platforms like LNL/ARL, we
> see the following 2 commands fail.
>
> perf stat $cputype -e '{instructions,slots},topdown-retiring' true
> perf stat $cputype -e '{instructions,slots},{topdown-retiring}' true
>
> Take the 1st command as an example, 5 events are created on hybrid
> platform. They are cpu_atom/instructions/, cpu_core/instructions/,
> cpu_core/slots/, cpu_atom/topdown-retiring/ and
> cpu_core/topdown-retiring/ events. The former 3 events are in a group
> and the latter 2 topdown-retiring events are independent events.
>
> As the limitation of current implementation, the
> cpu_core/topdown-retiring/ event can't be moved into previous group as
> long as there are other events before it. That's the reason why we see
> the failure.
>
> Thus add "--cputype core" option to limit only P-core events are tested.
>
> Signed-off-by: Dapeng Mi <dapeng1.mi@...ux.intel.com>
> ---
> tools/perf/arch/x86/util/evlist.c | 26 +++++++++++++++++++++++---
> tools/perf/tests/shell/stat.sh | 20 ++++++++++++++++++--
> 2 files changed, 41 insertions(+), 5 deletions(-)
>
> diff --git a/tools/perf/arch/x86/util/evlist.c b/tools/perf/arch/x86/util/evlist.c
> index 447a734e591c..0a71ba975871 100644
> --- a/tools/perf/arch/x86/util/evlist.c
> +++ b/tools/perf/arch/x86/util/evlist.c
> @@ -9,7 +9,7 @@ int arch_evlist__cmp(const struct evsel *lhs, const struct evsel *rhs)
> {
> /*
> * Currently the following topdown events sequence are supported to
> - * move and regroup correctly.
> + * move and regroup correctly on non-hybrid platforms.
> *
> * a. all events in a group
> * perf stat -e "{instructions,topdown-retiring,slots}" -C0 sleep 1
> @@ -44,7 +44,7 @@ int arch_evlist__cmp(const struct evsel *lhs, const struct evsel *rhs)
> * topdown metrics events must be first event after the slots event group,
> * otherwise topdown metrics events can't be regrouped correctly, e.g.
> *
> - * a. perf stat -e "{instructions,slots},cycles,topdown-retiring" -C0 sleep 1
> + * e. perf stat -e "{instructions,slots},cycles,topdown-retiring" -C0 sleep 1
> * WARNING: events were regrouped to match PMUs
> * Performance counter stats for 'CPU(s) 0':
> * 17,923,134 slots
> @@ -56,11 +56,31 @@ int arch_evlist__cmp(const struct evsel *lhs, const struct evsel *rhs)
> * has topdown metrics events must contain only the topdown metrics event,
> * otherwise topdown metrics event can't be regrouped correctly as well, e.g.
> *
> - * a. perf stat -e "{instructions,slots},{topdown-retiring,cycles}" -C0 sleep 1
> + * f. perf stat -e "{instructions,slots},{topdown-retiring,cycles}" -C0 sleep 1
> * WARNING: events were regrouped to match PMUs
> * Error:
> * The sys_perf_event_open() syscall returned with 22 (Invalid argument) for
> * event (topdown-retiring)
> + *
> + * For hybrid platforms, the sequences 'c' and 'd' are not supported as well
> + * besides above sequences 'e' and 'f'.
> + *
> + * perf stat -e "{instructions,slots},topdown-retiring" -C0 sleep 1
> + * perf stat -e "{instructions,slots},{topdown-retiring}" -C0 sleep 1
> + *
> + * On hybrid platforms each event would create an instance on all types of PMU
> + * if the event can be supported by the PMU, i.e., the "topdown-retiring" event
> + * would create two instances on hybrid platforms with P-cores and E-cores,
> + * "cpu_core/topdown-retiring/" and "cpu_atom/topdown_retiring".
> + *
> + * Take the first command as an example, the events list would be converted to
> + * below list in fact.
> + *
> + * "{cpu_atom/instructions/,cpu_core/instructions/,cpu_core/slots/},
> + * cpu_atom/topdown-retiring/,cpu_core/topdown-retiring/"
> + *
> + * This is actually same with event list in case 'e', "cpu_core/topdown-retiring/"
> + * event can't be moved into previous events group.
> */
> if (topdown_sys_has_perf_metrics() &&
> (arch_evsel__must_be_in_group(lhs) || arch_evsel__must_be_in_group(rhs))) {
> diff --git a/tools/perf/tests/shell/stat.sh b/tools/perf/tests/shell/stat.sh
> index 68323d636fb7..cdfe27c25528 100755
> --- a/tools/perf/tests/shell/stat.sh
> +++ b/tools/perf/tests/shell/stat.sh
> @@ -5,6 +5,16 @@
> set -e
>
> err=0
> +is_hybrid=false
> +
> +check_hybrid_platform() {
> + pmus=$(ls /sys/bus/event_source/devices/*/cpus 2>/dev/null | wc -l)
> + if [ "$pmus" -gt 1 ]
> + then
> + is_hybrid=true
> + fi
> +}
> +
> test_default_stat() {
> echo "Basic stat command test"
> if ! perf stat true 2>&1 | grep -E -q "Performance counter stats for 'true':"
> @@ -62,6 +72,11 @@ test_topdown_groups() {
> # Topdown events must be grouped with the slots event first. Test that
> # parse-events reorders this.
> echo "Topdown event group test"
> + cputype=""
> + if $is_hybrid
> + then
> + cputype="--cputype core"
> + fi
> if ! perf stat -e '{slots,topdown-retiring}' true > /dev/null 2>&1
> then
> echo "Topdown event group test [Skipped event parsing failed]"
> @@ -85,13 +100,13 @@ test_topdown_groups() {
> err=1
> return
> fi
> - if perf stat -e '{instructions,slots},topdown-retiring' true 2>&1 | grep -E -q "<not supported>"
> + if perf stat $cputype -e '{instructions,slots},topdown-retiring' true 2>&1 | grep -E -q "<not supported>"
So I can make this test fail on non-hybrid with:
```
$ perf stat -e '{instructions,slots},faults,topdown-retiring' true
WARNING: events were regrouped to match PMUs
Performance counter stats for 'true':
5,312,770 slots
1,078,401 instructions
56 faults
<not supported> topdown-retiring
```
The issue is that the slots isn't a group leader, so the "force group
index" we try to insert must be grouped events into is miscalculated
to be topdown-retiring. The following fixes this:
```
diff --git a/tools/perf/util/parse-events.c b/tools/perf/util/parse-events.c
index 35e48fe56dfa..68ddc335cde4 100644
--- a/tools/perf/util/parse-events.c
+++ b/tools/perf/util/parse-events.c
@@ -2056,8 +2056,7 @@ static int
parse_events__sort_events_and_fix_groups(struct list_head *list)
pos->core.idx = idx++;
/* Remember an index to sort all forced grouped events
together to. */
- if (force_grouped_idx == -1 && pos == pos_leader &&
pos->core.nr_members < 2 &&
- arch_evsel__must_be_in_group(pos))
+ if (force_grouped_idx == -1 &&
arch_evsel__must_be_in_group(pos))
force_grouped_idx = pos->core.idx;
}
```
> then
> echo "Topdown event group test [Failed topdown metrics event not move into slots group]"
> err=1
> return
> fi
> - if perf stat -e '{instructions,slots},{topdown-retiring}' true 2>&1 | grep -E -q "<not supported>"
> + if perf stat $cputype -e '{instructions,slots},{topdown-retiring}' true 2>&1 | grep -E -q "<not supported>"
So this is trickier as '{topdown-retiring}' ends up looking as a 2
event group. I'll post a proposed fix.
Thanks,
Ian
> then
> echo "Topdown event group test [Failed topdown metrics group not merge into slots group]"
> err=1
> @@ -200,6 +215,7 @@ test_hybrid() {
> echo "hybrid test [Success]"
> }
>
> +check_hybrid_platform
> test_default_stat
> test_stat_record_report
> test_stat_record_script
> --
> 2.40.1
>
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