From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ian Rogers Subject: Re: Issue of metrics for multiple uncore PMUs (was Re: [RFC PATCH v2 23/23] perf metricgroup: remove duped metric group events) Date: Mon, 5 Oct 2020 09:28:20 -0700 Message-ID: References: <20200507140819.126960-1-irogers@google.com> <20200507140819.126960-24-irogers@google.com> <757974b3-62b0-2822-84fb-1e75907c6cc4@huawei.com> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Return-path: In-Reply-To: <757974b3-62b0-2822-84fb-1e75907c6cc4@huawei.com> To: John Garry Cc: Peter Zijlstra , Ingo Molnar , Arnaldo Carvalho de Melo , Mark Rutland , Alexander Shishkin , Jiri Olsa , Namhyung Kim , Alexei Starovoitov , Daniel Borkmann , Martin KaFai Lau , Song Liu , Yonghong Song , Andrii Nakryiko , John Fastabend , KP Singh , Kajol Jain , Andi Kleen , Jin Yao , Kan Liang , Cong Wang Kim List-Id: linux-perf-users.vger.kernel.org On Mon, Oct 5, 2020 at 3:06 AM John Garry wrote: > > On 02/10/2020 21:46, Ian Rogers wrote: > > On Fri, Oct 2, 2020 at 5:00 AM John Garry wrote: > >> > >> 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? > > > > Sorry for this, I hadn't tested such a metric and wasn't aware of how > > the aliasing worked. I sent a fix for this issue here: > > https://lore.kernel.org/lkml/20200917201807.4090224-1-irogers@google.com/ > > Could you see if this addresses the issue for you? I don't see the > > change in Arnaldo's trees yet. > > Unfortunately this does not seem to fix my issue. > > So for that patch, you say you fix metric expression for DRAM_BW_Use, > which is: > > { > "BriefDescription": "Average external Memory Bandwidth Use for reads > and writes [GB / sec]", > "MetricExpr": "( 64 * ( uncore_imc@cas_count_read@ + > uncore_imc@cas_count_write@ ) / 1000000000 ) / duration_time", > "MetricGroup": "Memory_BW", > "MetricName": "DRAM_BW_Use" > }, > > But this metric expression does not include any alias events; rather I > think it is just cas_count_write + cas_count_read event count for PMU > uncore_imc / duration_time. > > When I say alias, I mean - as an example, we have event: > > { > "BriefDescription": "write requests to memory controller. > Derived from unc_m_cas_count.wr", > "Counter": "0,1,2,3", > "EventCode": "0x4", > "EventName": "LLC_MISSES.MEM_WRITE", > "PerPkg": "1", > "ScaleUnit": "64Bytes", > "UMask": "0xC", > "Unit": "iMC" > }, > > And then reference LLC_MISSES.MEM_WRITE in a metric expression: > > "MetricExpr": "LLC_MISSES.MEM_WRITE / duration_time", > > This is what seems to be broken for when the alias matches > 1 PMU. > > Please check this. Happy to check. Can you provide a reproduction? Looking on broadwell this metric doesn't exist. Thanks, Ian > Thanks, > John > > > > > Thanks, > > Ian > > > >> 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: > > . > > >