Messages in this thread Patch in this message | | | Subject | Issue of metrics for multiple uncore PMUs (was Re: [RFC PATCH v2 23/23] perf metricgroup: remove duped metric group events) | From | John Garry <> | Date | Fri, 2 Oct 2020 12:57:04 +0100 |
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On 07/05/2020 15:08, Ian Rogers wrote:
Hi Ian,
I was wondering if you ever tested commit 2440689d62e9 ("perf metricgroup: Remove duped metric group events") for when we have a metric which aliases multiple instances of the same uncore PMU in the system?
I have been rebasing some of my arm64 perf work to v5.9-rc7, and find an issue where find_evsel_group() fails for the uncore metrics under the condition mentioned above.
Unfortunately I don't have an x86 machine to which this test applies. However, as an experiment, I added a test metric to my broadwell JSON:
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" } ]
And get this:
john@localhost:~/linux/tools/perf> sudo ./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/ Cannot resolve test_metric_inc: unc_cbo_xsnp_response.miss_xcore * unc_cbo_xsnp_response.miss_eviction task-clock: 688876 688876 688876 context-switches: 2 688876 688876 cpu-migrations: 0 688876 688876 page-faults: 69 688876 688876 cycles: 2101719 695690 695690 instructions: 1180534 695690 695690 branches: 249450 695690 695690 branch-misses: 10815 695690 695690 Performance counter stats for 'sleep 1':
0.69 msec task-clock # 0.001 CPUs utilized 2 context-switches # 0.003 M/sec
0 cpu-migrations # 0.000 K/sec
69 page-faults # 0.100 M/sec
2,101,719 cycles # 3.051 GHz
1,180,534 instructions # 0.56 insn per cycle 249,450 branches # 362.112 M/sec
10,815 branch-misses # 4.34% of all branches
1.001177693 seconds time elapsed
0.001149000 seconds user 0.000000000 seconds sys
john@localhost:~/linux/tools/perf>
Any idea what is going wrong here, before I have to dive in? The issue seems to be this named commit.
Thanks, John
> A metric group contains multiple metrics. These metrics may use the same > events. If metrics use separate events then it leads to more > multiplexing and overall metric counts fail to sum to 100%. > Modify how metrics are associated with events so that if the events in > an earlier group satisfy the current metric, the same events are used. > A record of used events is kept and at the end of processing unnecessary > events are eliminated. > > Before:
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