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
next prev 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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