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Message-ID: <3e2ee47f-d351-64c3-b547-993a2b65f871@linux.intel.com>
Date: Tue, 31 Mar 2020 15:30:25 -0400
From: "Liang, Kan" <kan.liang@...ux.intel.com>
To: Jin Yao <yao.jin@...ux.intel.com>, acme@...nel.org,
jolsa@...nel.org, peterz@...radead.org, mingo@...hat.com,
alexander.shishkin@...ux.intel.com
Cc: Linux-kernel@...r.kernel.org, ak@...ux.intel.com,
kan.liang@...el.com, yao.jin@...el.com
Subject: Re: [PATCH] perf/x86/pmu-events: Use CPU_CLK_UNHALTED.THREAD in
Kernel_Utilization metric
On 3/8/2020 9:31 PM, 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@...ux.intel.com>
Reviewed-by: Kan Liang <kan.liang@...ux.intel.com>
Thanks,
Kan
> ---
> 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"
> },
>
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