Messages in this thread | | | Date | Tue, 27 Oct 2020 13:20:18 -0300 | From | Arnaldo Carvalho de Melo <> | Subject | Re: [PATCH] perf vendor events: Fix DRAM_BW_Use 0 issue for CLX/SKX |
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Em Thu, Oct 22, 2020 at 06:02:31PM -0700, Ian Rogers escreveu: > On Thu, Oct 22, 2020 at 5:54 PM Jin Yao <yao.jin@linux.intel.com> wrote: > > > > Ian reports an issue that the metric DRAM_BW_Use often remains 0. > > > > The metric expression for DRAM_BW_Use on CLX/SKX: > > > > "( 64 * ( uncore_imc@cas_count_read@ + uncore_imc@cas_count_write@ ) / 1000000000 ) / duration_time" > > > > The counts of uncore_imc/cas_count_read/ and uncore_imc/cas_count_write/ > > are scaled up by 64, that is to turn a count of cache lines into bytes, > > the count is then divided by 1000000000 to give GB. > > > > However, the counts of uncore_imc/cas_count_read/ and > > uncore_imc/cas_count_write/ have been scaled yet. > > > > The scale values are from sysfs, such as > > /sys/devices/uncore_imc_0/events/cas_count_read.scale. > > It's 6.103515625e-5 (64 / 1024.0 / 1024.0). > > > > So if we use original metric expression, the result is not correct. > > > > But the difficulty is, for SKL client, the counts are not scaled. > > > > The metric expression for DRAM_BW_Use on SKL: > > > > "64 * ( arb@event\\=0x81\\,umask\\=0x1@ + arb@event\\=0x84\\,umask\\=0x1@ ) / 1000000 / duration_time / 1000" > > > > root@kbl-ppc:~# perf stat -M DRAM_BW_Use -a -- sleep 1 > > > > Performance counter stats for 'system wide': > > > > 190 arb/event=0x84,umask=0x1/ # 1.86 DRAM_BW_Use > > 29,093,178 arb/event=0x81,umask=0x1/ > > 1,000,703,287 ns duration_time > > > > 1.000703287 seconds time elapsed > > > > The result is expected. > > > > So the easy way is just change the metric expression for CLX/SKX. > > This patch changes the metric expression to: > > > > "( ( ( uncore_imc@cas_count_read@ + uncore_imc@cas_count_write@ ) * 1048576 ) / 1000000000 ) / duration_time" > > > > 1048576 = 1024 * 1024. > > > > Before (tested on CLX): > > > > root@lkp-csl-2sp5 ~# perf stat -M DRAM_BW_Use -a -- sleep 1 > > > > Performance counter stats for 'system wide': > > > > 765.35 MiB uncore_imc/cas_count_read/ # 0.00 DRAM_BW_Use > > 5.42 MiB uncore_imc/cas_count_write/ > > 1001515088 ns duration_time > > > > 1.001515088 seconds time elapsed > > > > After: > > > > root@lkp-csl-2sp5 ~# perf stat -M DRAM_BW_Use -a -- sleep 1 > > > > Performance counter stats for 'system wide': > > > > 767.95 MiB uncore_imc/cas_count_read/ # 0.80 DRAM_BW_Use > > Nit, using ScaleUnit would allow this to be 0.80GB/s. > > > 5.02 MiB uncore_imc/cas_count_write/ > > 1001900010 ns duration_time > > > > 1.001900010 seconds time elapsed > > > > Fixes: 038d3b53c284 ("perf vendor events intel: Update CascadelakeX events to v1.08") > > Fixes: b5ff7f2799a4 ("perf vendor events: Update SkylakeX events to v1.21") > > Signed-off-by: Jin Yao <yao.jin@linux.intel.com> > > Acked-by: Ian Rogers <irogers@google.com>
Thanks, applied.
- Arnaldo
> Thanks, > Ian > > > --- > > tools/perf/pmu-events/arch/x86/cascadelakex/clx-metrics.json | 2 +- > > tools/perf/pmu-events/arch/x86/skylakex/skx-metrics.json | 2 +- > > 2 files changed, 2 insertions(+), 2 deletions(-) > > > > diff --git a/tools/perf/pmu-events/arch/x86/cascadelakex/clx-metrics.json b/tools/perf/pmu-events/arch/x86/cascadelakex/clx-metrics.json > > index de3193552277..00f4fcffa815 100644 > > --- a/tools/perf/pmu-events/arch/x86/cascadelakex/clx-metrics.json > > +++ b/tools/perf/pmu-events/arch/x86/cascadelakex/clx-metrics.json > > @@ -329,7 +329,7 @@ > > }, > > { > > "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", > > + "MetricExpr": "( ( ( uncore_imc@cas_count_read@ + uncore_imc@cas_count_write@ ) * 1048576 ) / 1000000000 ) / duration_time", > > "MetricGroup": "Memory_BW;SoC", > > "MetricName": "DRAM_BW_Use" > > }, > > diff --git a/tools/perf/pmu-events/arch/x86/skylakex/skx-metrics.json b/tools/perf/pmu-events/arch/x86/skylakex/skx-metrics.json > > index f31794d3b926..0dd8b13b5cfb 100644 > > --- a/tools/perf/pmu-events/arch/x86/skylakex/skx-metrics.json > > +++ b/tools/perf/pmu-events/arch/x86/skylakex/skx-metrics.json > > @@ -323,7 +323,7 @@ > > }, > > { > > "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", > > + "MetricExpr": "( ( ( uncore_imc@cas_count_read@ + uncore_imc@cas_count_write@ ) * 1048576 ) / 1000000000 ) / duration_time", > > "MetricGroup": "Memory_BW;SoC", > > "MetricName": "DRAM_BW_Use" > > }, > > -- > > 2.17.1 > >
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- Arnaldo
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