linux-kernel - Re: Issue of metrics for multiple uncore PMUs (was Re: [RFC PATCH v2 23/23] perf metricgroup: remove duped metric group events)

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Date:   Tue, 6 Oct 2020 15:19:13 +0100
From:   John Garry <john.garry@...wei.com>
To:     Ian Rogers <irogers@...gle.com>
CC:     Peter Zijlstra <peterz@...radead.org>,
        Ingo Molnar <mingo@...hat.com>,
        Arnaldo Carvalho de Melo <acme@...nel.org>,
        Mark Rutland <mark.rutland@....com>,
        Alexander Shishkin <alexander.shishkin@...ux.intel.com>,
        Jiri Olsa <jolsa@...hat.com>,
        Namhyung Kim <namhyung@...nel.org>,
        Alexei Starovoitov <ast@...nel.org>,
        Daniel Borkmann <daniel@...earbox.net>,
        Martin KaFai Lau <kafai@...com>,
        Song Liu <songliubraving@...com>, Yonghong Song <yhs@...com>,
        Andrii Nakryiko <andriin@...com>,
        John Fastabend <john.fastabend@...il.com>,
        KP Singh <kpsingh@...omium.org>,
        Kajol Jain <kjain@...ux.ibm.com>,
        Andi Kleen <ak@...ux.intel.com>,
        Jin Yao <yao.jin@...ux.intel.com>,
        Kan Liang <kan.liang@...ux.intel.com>,
        Cong Wang <xiyou.wangcong@...il.com>,
        Kim Phillips <kim.phillips@....com>,
        LKML <linux-kernel@...r.kernel.org>,
        Networking <netdev@...r.kernel.org>, bpf <bpf@...r.kernel.org>,
        linux-perf-users <linux-perf-users@...r.kernel.org>,
        Stephane Eranian <eranian@...gle.com>
Subject: Re: Issue of metrics for multiple uncore PMUs (was Re: [RFC PATCH v2
 23/23] perf metricgroup: remove duped metric group events)

On 05/10/2020 19:05, John Garry wrote:
>> Can you provide a reproduction? Looking on broadwell
>> this metric doesn't exist.
> 
> Right, I just added this test metric as my 2x x86 platform has no 
> examples which I can find:
> 
> diff --git a/tools/perf/pmu-events/arch/x86/broadwell/bdw-metrics.json 
> b/tools/perf/pmu-events/arch/x86/broadwell/bdw-metrics.json
> index 8cdc7c13dc2a..fc6d9adf996a 100644
> --- a/tools/perf/pmu-events/arch/x86/broadwell/bdw-metrics.json
> +++ b/tools/perf/pmu-events/arch/x86/broadwell/bdw-metrics.json
> @@ -348,5 +348,11 @@
>          "MetricExpr": "(cstate_pkg@c7\\-residency@ / msr@tsc@) * 100",
>          "MetricGroup": "Power",
>          "MetricName": "C7_Pkg_Residency"
> +    },
> +    {
> +        "BriefDescription": "test metric",
> +        "MetricExpr": "UNC_CBO_XSNP_RESPONSE.MISS_XCORE * 
> UNC_CBO_XSNP_RESPONSE.MISS_EVICTION",
> +        "MetricGroup": "Test",
> +        "MetricName": "test_metric_inc"
>      }
> ]
> 

It seems that the code in find_evsel_group() does not properly handle 
the scenario of event alias matching different PMUs (as I already said).

So I got it working on top of "perf metricgroup: Fix uncore metric 
expressions" with the following change:

diff --git a/tools/perf/util/metricgroup.c b/tools/perf/util/metricgroup.c
index d948a7f910cf..6293378c019c 100644
--- a/tools/perf/util/metricgroup.c
+++ b/tools/perf/util/metricgroup.c
@@ -213,7 +213,8 @@ static struct evsel *find_evsel_group(struct evlist 
*perf_evlist,
  		/* Ignore event if already used and merging is disabled. */
  		if (metric_no_merge && test_bit(ev->idx, evlist_used))
  			continue;
-		if (!has_constraint && ev->leader != current_leader) {
+		if (!has_constraint && (!current_leader || 
strcmp(current_leader->name, ev->leader->name))) {
  			/*
  			 * Start of a new group, discard the whole match and
  			 * start again.
@@ -279,7 +280,8 @@ static struct evsel *find_evsel_group(struct evlist 
*perf_evlist,
  			 * when then group is left.
  			 */
  			if (!has_constraint &&
-			    ev->leader != metric_events[i]->leader)
+			    strcmp(ev->leader->name, metric_events[i]->leader->name))
  				break;
  			if (!strcmp(metric_events[i]->name, ev->name)) {
  				set_bit(ev->idx, evlist_used);

which gives for my test metric:

./perf stat -v -M test_metric_inc sleep 1
Using CPUID GenuineIntel-6-3D-4
metric expr unc_cbo_xsnp_response.miss_xcore / 
unc_cbo_xsnp_response.miss_eviction for test_metric_inc
found event unc_cbo_xsnp_response.miss_eviction
found event unc_cbo_xsnp_response.miss_xcore
adding 
{unc_cbo_xsnp_response.miss_eviction,unc_cbo_xsnp_response.miss_xcore}:W
unc_cbo_xsnp_response.miss_eviction -> uncore_cbox_1/umask=0x81,event=0x22/
unc_cbo_xsnp_response.miss_eviction -> uncore_cbox_0/umask=0x81,event=0x22/
unc_cbo_xsnp_response.miss_xcore -> uncore_cbox_1/umask=0x41,event=0x22/
unc_cbo_xsnp_response.miss_xcore -> uncore_cbox_0/umask=0x41,event=0x22/
Control descriptor is not initialized
unc_cbo_xsnp_response.miss_eviction: 595175 1001021311 1001021311
unc_cbo_xsnp_response.miss_eviction: 592516 1001020037 1001020037
unc_cbo_xsnp_response.miss_xcore: 39139 1001021311 1001021311
unc_cbo_xsnp_response.miss_xcore: 38718 1001020037 1001020037

Performance counter stats for 'system wide':

         1,187,691      unc_cbo_xsnp_response.miss_eviction #     0.07 
test_metric_inc
            77,857      unc_cbo_xsnp_response.miss_xcore 


       1.001068918 seconds time elapsed

John