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From: Jiri Olsa <jolsa@redhat.com>
To: kan.liang@intel.com
Cc: peterz@infradead.org, mingo@redhat.com, acme@kernel.org,
	linux-kernel@vger.kernel.org, alexander.shishkin@linux.intel.com,
	tglx@linutronix.de, namhyung@kernel.org, jolsa@kernel.org,
	adrian.hunter@intel.com, wangnan0@huawei.com,
	mark.rutland@arm.com, andi@firstfloor.org
Subject: Re: [PATCH V2 08/13] perf tools: show kernel overhead
Date: Tue, 6 Dec 2016 12:16:23 +0100	[thread overview]
Message-ID: <20161206111623.GC7730@krava> (raw)
In-Reply-To: <1480713561-6617-9-git-send-email-kan.liang@intel.com>

On Fri, Dec 02, 2016 at 04:19:16PM -0500, kan.liang@intel.com wrote:

SNIP

>  --show-profiling-cost:
>  	Show extra time cost during perf profiling
> +	Sort the extra time cost by CPU
> +	If CPU information is not available in perf_sample, using -1 instead.
> +	The time cost include:
> +	- SAM: sample overhead. For x86, it's the time cost in perf NMI handler.
> +	- MUX: multiplexing overhead. The time cost spends on rotate context.
> +	- SB: side-band events overhead. The time cost spends on iterating all
> +	      events that need to receive side-band events.
>  
>  include::callchain-overhead-calculation.txt[]
>  
> diff --git a/tools/perf/util/event.h b/tools/perf/util/event.h
> index d96e215..dd4ec5c 100644
> --- a/tools/perf/util/event.h
> +++ b/tools/perf/util/event.h
> @@ -245,6 +245,12 @@ enum auxtrace_error_type {
>  	PERF_AUXTRACE_ERROR_MAX
>  };
>  
> +struct total_overhead {
> +	struct perf_overhead_entry	total_sample[MAX_NR_CPUS + 1];
> +	struct perf_overhead_entry	total_mux[MAX_NR_CPUS + 1];
> +	struct perf_overhead_entry	total_sb[MAX_NR_CPUS + 1];
> +};

I think this should be either:
   - dynamically allocated (there's cpu count available in the session)
   - or made static within perf report (as in shadow stats) and counted
     in report's overhead tool callback

I also don't like that you do the process-related counts
in the xxx[MAX_NR_CPUS] member, we should have separated
struct perf_overhead_entry for that

jirla

  parent reply	other threads:[~2016-12-06 11:16 UTC|newest]

Thread overview: 33+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-12-02 21:19 [PATCH V2 00/13] export perf overheads information kan.liang
2016-12-02 21:19 ` [PATCH V2 01/13] perf/core: Introduce PERF_RECORD_OVERHEAD kan.liang
2016-12-06 11:26   ` Peter Zijlstra
2016-12-02 21:19 ` [PATCH V2 02/13] perf/core: output overhead when sched out from context kan.liang
2016-12-06 11:21   ` Peter Zijlstra
2016-12-02 21:19 ` [PATCH V2 03/13] perf/x86: output sampling overhead kan.liang
2016-12-06 11:20   ` Peter Zijlstra
2016-12-06 15:02     ` Liang, Kan
2016-12-06 15:32       ` Peter Zijlstra
2016-12-06 15:47         ` Liang, Kan
2016-12-06 18:26           ` Peter Zijlstra
2016-12-07 19:03             ` Liang, Kan
2016-12-06 11:38   ` Peter Zijlstra
2016-12-02 21:19 ` [PATCH V2 04/13] perf/core: output multiplexing overhead kan.liang
2016-12-06 11:23   ` Peter Zijlstra
2016-12-06 15:04     ` Liang, Kan
2016-12-02 21:19 ` [PATCH V2 05/13] perf/core: output side-band events overhead kan.liang
2016-12-06 11:25   ` Peter Zijlstra
2016-12-02 21:19 ` [PATCH V2 06/13] perf tools: option to disable overhead collection kan.liang
2016-12-02 21:19 ` [PATCH V2 07/13] perf tools: handle PERF_RECORD_OVERHEAD record type kan.liang
2016-12-06 11:16   ` Jiri Olsa
2016-12-02 21:19 ` [PATCH V2 08/13] perf tools: show kernel overhead kan.liang
2016-12-06 11:16   ` Jiri Olsa
2016-12-06 11:16   ` Jiri Olsa [this message]
2016-12-06 11:16   ` Jiri Olsa
2016-12-02 21:19 ` [PATCH V2 09/13] perf script: " kan.liang
2016-12-04 21:25   ` Jiri Olsa
2016-12-05 14:47     ` Liang, Kan
2016-12-02 21:19 ` [PATCH V2 10/13] perf tools: add time related functions kan.liang
2016-12-06 11:16   ` Jiri Olsa
2016-12-02 21:19 ` [PATCH V2 11/13] perf tools: introduce PERF_RECORD_USER_OVERHEAD kan.liang
2016-12-02 21:19 ` [PATCH V2 12/13] perf tools: record user space profiling cost kan.liang
2016-12-02 21:19 ` [PATCH V2 13/13] perf report: warn on high overhead kan.liang

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