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From:   Arnaldo Carvalho de Melo <arnaldo.melo@gmail.com>
Date:   Tue, 31 Mar 2020 16:08:04 -0300
To:     "Jin, Yao" <yao.jin@linux.intel.com>
Cc:     jolsa@kernel.org, peterz@infradead.org, mingo@redhat.com,
        alexander.shishkin@linux.intel.com, Linux-kernel@vger.kernel.org,
        ak@linux.intel.com, kan.liang@intel.com, yao.jin@intel.com
Subject: Re: [PATCH] perf/x86/pmu-events: Use CPU_CLK_UNHALTED.THREAD in
 Kernel_Utilization metric
Message-ID: <20200331190804.GK9917@kernel.org>
References: <20200309013125.7559-1-yao.jin@linux.intel.com>
 <f335f8ec-f92e-787e-0594-00cec2e06036@linux.intel.com>
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Em Mon, Mar 30, 2020 at 08:38:29AM +0800, Jin, Yao escreveu:
> Hi,
> 
> Any comments for this patch?

Can someone help Jin reviewing this x86 specific metric?

- Arnaldo
 
> Thanks
> Jin Yao
> 
> On 3/9/2020 9:31 AM, Jin Yao wrote:
> > The kernel utilization metric does multiplexing currently and is somewhat
> > unreliable. The problem is that it uses two instances of the fixed counter,
> > and the kernel has to multipleplex which causes errors. So should use
> > CPU_CLK_UNHALTED.THREAD instead.
> > 
> > Before:
> > 
> >    # perf stat -M Kernel_Utilization -- sleep 1
> > 
> >    Performance counter stats for 'sleep 1':
> > 
> >            1,419,425      cpu_clk_unhalted.ref_tsc:k
> >        <not counted>      cpu_clk_unhalted.ref_tsc	(0.00%)
> > 
> > After:
> > 
> >    # perf stat -M Kernel_Utilization -- sleep 1
> > 
> >    Performance counter stats for 'sleep 1':
> > 
> >              746,688      cpu_clk_unhalted.thread:k #      0.7 Kernel_Utilization
> >            1,088,348      cpu_clk_unhalted.thread
> > 
> > Signed-off-by: Jin Yao <yao.jin@linux.intel.com>
> > ---
> >   tools/perf/pmu-events/arch/x86/broadwell/bdw-metrics.json     | 2 +-
> >   tools/perf/pmu-events/arch/x86/broadwellde/bdwde-metrics.json | 2 +-
> >   tools/perf/pmu-events/arch/x86/broadwellx/bdx-metrics.json    | 2 +-
> >   tools/perf/pmu-events/arch/x86/cascadelakex/clx-metrics.json  | 2 +-
> >   tools/perf/pmu-events/arch/x86/haswell/hsw-metrics.json       | 2 +-
> >   tools/perf/pmu-events/arch/x86/haswellx/hsx-metrics.json      | 2 +-
> >   tools/perf/pmu-events/arch/x86/ivybridge/ivb-metrics.json     | 2 +-
> >   tools/perf/pmu-events/arch/x86/ivytown/ivt-metrics.json       | 2 +-
> >   tools/perf/pmu-events/arch/x86/jaketown/jkt-metrics.json      | 2 +-
> >   tools/perf/pmu-events/arch/x86/sandybridge/snb-metrics.json   | 2 +-
> >   tools/perf/pmu-events/arch/x86/skylake/skl-metrics.json       | 2 +-
> >   tools/perf/pmu-events/arch/x86/skylakex/skx-metrics.json      | 2 +-
> >   12 files changed, 12 insertions(+), 12 deletions(-)
> > 
> > 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 45a34ce4fe89..8cdc7c13dc2a 100644
> > --- a/tools/perf/pmu-events/arch/x86/broadwell/bdw-metrics.json
> > +++ b/tools/perf/pmu-events/arch/x86/broadwell/bdw-metrics.json
> > @@ -297,7 +297,7 @@
> >       },
> >       {
> >           "BriefDescription": "Fraction of cycles spent in Kernel mode",
> > -        "MetricExpr": "CPU_CLK_UNHALTED.REF_TSC:k / CPU_CLK_UNHALTED.REF_TSC",
> > +        "MetricExpr": "CPU_CLK_UNHALTED.THREAD:k / CPU_CLK_UNHALTED.THREAD",
> >           "MetricGroup": "Summary",
> >           "MetricName": "Kernel_Utilization"
> >       },
> > diff --git a/tools/perf/pmu-events/arch/x86/broadwellde/bdwde-metrics.json b/tools/perf/pmu-events/arch/x86/broadwellde/bdwde-metrics.json
> > index 961fe4395758..16fd8a7490fc 100644
> > --- a/tools/perf/pmu-events/arch/x86/broadwellde/bdwde-metrics.json
> > +++ b/tools/perf/pmu-events/arch/x86/broadwellde/bdwde-metrics.json
> > @@ -115,7 +115,7 @@
> >       },
> >       {
> >           "BriefDescription": "Fraction of cycles spent in Kernel mode",
> > -        "MetricExpr": "CPU_CLK_UNHALTED.REF_TSC:k / CPU_CLK_UNHALTED.REF_TSC",
> > +        "MetricExpr": "CPU_CLK_UNHALTED.THREAD:k / CPU_CLK_UNHALTED.THREAD",
> >           "MetricGroup": "Summary",
> >           "MetricName": "Kernel_Utilization"
> >       },
> > diff --git a/tools/perf/pmu-events/arch/x86/broadwellx/bdx-metrics.json b/tools/perf/pmu-events/arch/x86/broadwellx/bdx-metrics.json
> > index 746734ce09be..1eb0415fa11a 100644
> > --- a/tools/perf/pmu-events/arch/x86/broadwellx/bdx-metrics.json
> > +++ b/tools/perf/pmu-events/arch/x86/broadwellx/bdx-metrics.json
> > @@ -297,7 +297,7 @@
> >       },
> >       {
> >           "BriefDescription": "Fraction of cycles spent in Kernel mode",
> > -        "MetricExpr": "CPU_CLK_UNHALTED.REF_TSC:k / CPU_CLK_UNHALTED.REF_TSC",
> > +        "MetricExpr": "CPU_CLK_UNHALTED.THREAD:k / CPU_CLK_UNHALTED.THREAD",
> >           "MetricGroup": "Summary",
> >           "MetricName": "Kernel_Utilization"
> >       },
> > 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 f94653229dd4..a2c32db8f14e 100644
> > --- a/tools/perf/pmu-events/arch/x86/cascadelakex/clx-metrics.json
> > +++ b/tools/perf/pmu-events/arch/x86/cascadelakex/clx-metrics.json
> > @@ -315,7 +315,7 @@
> >       },
> >       {
> >           "BriefDescription": "Fraction of cycles spent in Kernel mode",
> > -        "MetricExpr": "CPU_CLK_UNHALTED.REF_TSC:k / CPU_CLK_UNHALTED.REF_TSC",
> > +        "MetricExpr": "CPU_CLK_UNHALTED.THREAD:k / CPU_CLK_UNHALTED.THREAD",
> >           "MetricGroup": "Summary",
> >           "MetricName": "Kernel_Utilization"
> >       },
> > diff --git a/tools/perf/pmu-events/arch/x86/haswell/hsw-metrics.json b/tools/perf/pmu-events/arch/x86/haswell/hsw-metrics.json
> > index 5402cd3120f9..f57c5f3506c2 100644
> > --- a/tools/perf/pmu-events/arch/x86/haswell/hsw-metrics.json
> > +++ b/tools/perf/pmu-events/arch/x86/haswell/hsw-metrics.json
> > @@ -267,7 +267,7 @@
> >       },
> >       {
> >           "BriefDescription": "Fraction of cycles spent in Kernel mode",
> > -        "MetricExpr": "CPU_CLK_UNHALTED.REF_TSC:k / CPU_CLK_UNHALTED.REF_TSC",
> > +        "MetricExpr": "CPU_CLK_UNHALTED.THREAD:k / CPU_CLK_UNHALTED.THREAD",
> >           "MetricGroup": "Summary",
> >           "MetricName": "Kernel_Utilization"
> >       },
> > diff --git a/tools/perf/pmu-events/arch/x86/haswellx/hsx-metrics.json b/tools/perf/pmu-events/arch/x86/haswellx/hsx-metrics.json
> > index 832f3cb40b34..311a005dc35b 100644
> > --- a/tools/perf/pmu-events/arch/x86/haswellx/hsx-metrics.json
> > +++ b/tools/perf/pmu-events/arch/x86/haswellx/hsx-metrics.json
> > @@ -267,7 +267,7 @@
> >       },
> >       {
> >           "BriefDescription": "Fraction of cycles spent in Kernel mode",
> > -        "MetricExpr": "CPU_CLK_UNHALTED.REF_TSC:k / CPU_CLK_UNHALTED.REF_TSC",
> > +        "MetricExpr": "CPU_CLK_UNHALTED.THREAD:k / CPU_CLK_UNHALTED.THREAD",
> >           "MetricGroup": "Summary",
> >           "MetricName": "Kernel_Utilization"
> >       },
> > diff --git a/tools/perf/pmu-events/arch/x86/ivybridge/ivb-metrics.json b/tools/perf/pmu-events/arch/x86/ivybridge/ivb-metrics.json
> > index d69b2a8fc0bc..28e25447d3ef 100644
> > --- a/tools/perf/pmu-events/arch/x86/ivybridge/ivb-metrics.json
> > +++ b/tools/perf/pmu-events/arch/x86/ivybridge/ivb-metrics.json
> > @@ -285,7 +285,7 @@
> >       },
> >       {
> >           "BriefDescription": "Fraction of cycles spent in Kernel mode",
> > -        "MetricExpr": "CPU_CLK_UNHALTED.REF_TSC:k / CPU_CLK_UNHALTED.REF_TSC",
> > +        "MetricExpr": "CPU_CLK_UNHALTED.THREAD:k / CPU_CLK_UNHALTED.THREAD",
> >           "MetricGroup": "Summary",
> >           "MetricName": "Kernel_Utilization"
> >       },
> > diff --git a/tools/perf/pmu-events/arch/x86/ivytown/ivt-metrics.json b/tools/perf/pmu-events/arch/x86/ivytown/ivt-metrics.json
> > index 5f465fd81315..db23db2e98be 100644
> > --- a/tools/perf/pmu-events/arch/x86/ivytown/ivt-metrics.json
> > +++ b/tools/perf/pmu-events/arch/x86/ivytown/ivt-metrics.json
> > @@ -285,7 +285,7 @@
> >       },
> >       {
> >           "BriefDescription": "Fraction of cycles spent in Kernel mode",
> > -        "MetricExpr": "CPU_CLK_UNHALTED.REF_TSC:k / CPU_CLK_UNHALTED.REF_TSC",
> > +        "MetricExpr": "CPU_CLK_UNHALTED.THREAD:k / CPU_CLK_UNHALTED.THREAD",
> >           "MetricGroup": "Summary",
> >           "MetricName": "Kernel_Utilization"
> >       },
> > diff --git a/tools/perf/pmu-events/arch/x86/jaketown/jkt-metrics.json b/tools/perf/pmu-events/arch/x86/jaketown/jkt-metrics.json
> > index 3e909b306003..dbb33e00b72a 100644
> > --- a/tools/perf/pmu-events/arch/x86/jaketown/jkt-metrics.json
> > +++ b/tools/perf/pmu-events/arch/x86/jaketown/jkt-metrics.json
> > @@ -171,7 +171,7 @@
> >       },
> >       {
> >           "BriefDescription": "Fraction of cycles spent in Kernel mode",
> > -        "MetricExpr": "CPU_CLK_UNHALTED.REF_TSC:k / CPU_CLK_UNHALTED.REF_TSC",
> > +        "MetricExpr": "CPU_CLK_UNHALTED.THREAD:k / CPU_CLK_UNHALTED.THREAD",
> >           "MetricGroup": "Summary",
> >           "MetricName": "Kernel_Utilization"
> >       },
> > diff --git a/tools/perf/pmu-events/arch/x86/sandybridge/snb-metrics.json b/tools/perf/pmu-events/arch/x86/sandybridge/snb-metrics.json
> > index 50c053235752..fb2d7b8875f8 100644
> > --- a/tools/perf/pmu-events/arch/x86/sandybridge/snb-metrics.json
> > +++ b/tools/perf/pmu-events/arch/x86/sandybridge/snb-metrics.json
> > @@ -171,7 +171,7 @@
> >       },
> >       {
> >           "BriefDescription": "Fraction of cycles spent in Kernel mode",
> > -        "MetricExpr": "CPU_CLK_UNHALTED.REF_TSC:k / CPU_CLK_UNHALTED.REF_TSC",
> > +        "MetricExpr": "CPU_CLK_UNHALTED.THREAD:k / CPU_CLK_UNHALTED.THREAD",
> >           "MetricGroup": "Summary",
> >           "MetricName": "Kernel_Utilization"
> >       },
> > diff --git a/tools/perf/pmu-events/arch/x86/skylake/skl-metrics.json b/tools/perf/pmu-events/arch/x86/skylake/skl-metrics.json
> > index e7feb60f9fa9..e3afc3178958 100644
> > --- a/tools/perf/pmu-events/arch/x86/skylake/skl-metrics.json
> > +++ b/tools/perf/pmu-events/arch/x86/skylake/skl-metrics.json
> > @@ -303,7 +303,7 @@
> >       },
> >       {
> >           "BriefDescription": "Fraction of cycles spent in Kernel mode",
> > -        "MetricExpr": "CPU_CLK_UNHALTED.REF_TSC:k / CPU_CLK_UNHALTED.REF_TSC",
> > +        "MetricExpr": "CPU_CLK_UNHALTED.THREAD:k / CPU_CLK_UNHALTED.THREAD",
> >           "MetricGroup": "Summary",
> >           "MetricName": "Kernel_Utilization"
> >       },
> > 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 21d7a0c2c2e8..12d1efba79bb 100644
> > --- a/tools/perf/pmu-events/arch/x86/skylakex/skx-metrics.json
> > +++ b/tools/perf/pmu-events/arch/x86/skylakex/skx-metrics.json
> > @@ -315,7 +315,7 @@
> >       },
> >       {
> >           "BriefDescription": "Fraction of cycles spent in Kernel mode",
> > -        "MetricExpr": "CPU_CLK_UNHALTED.REF_TSC:k / CPU_CLK_UNHALTED.REF_TSC",
> > +        "MetricExpr": "CPU_CLK_UNHALTED.THREAD:k / CPU_CLK_UNHALTED.THREAD",
> >           "MetricGroup": "Summary",
> >           "MetricName": "Kernel_Utilization"
> >       },
> > 

-- 

- Arnaldo