Re: [PATCH] perf/x86/pmu-events: Use CPU_CLK_UNHALTED.THREAD in Kernel_Utilization metric

From: Andi Kleen
Date: Tue Mar 31 2020 - 16:04:16 EST


On Tue, Mar 31, 2020 at 04:08:04PM -0300, Arnaldo Carvalho de Melo wrote:
> 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?

Looks good to me.

Reviewed-by: Andi Kleen <ak@xxxxxxxxxxxxxxx>
>
> - 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@xxxxxxxxxxxxxxx>
> > > ---
> > > 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