From: Ingo Molnar <mingo@kernel.org>
To: kan.liang@linux.intel.com
Cc: peterz@infradead.org, acme@kernel.org,
linux-kernel@vger.kernel.org, jolsa@kernel.org,
namhyung@kernel.org, ak@linux.intel.com,
vitaly.slobodskoy@intel.com, pavel.gerasimov@intel.com
Subject: Re: [PATCH 00/10] Stitch LBR call stack
Date: Mon, 7 Oct 2019 20:24:35 +0200 [thread overview]
Message-ID: <20191007182435.GA97660@gmail.com> (raw)
In-Reply-To: <20191007175910.2805-1-kan.liang@linux.intel.com>
* kan.liang@linux.intel.com <kan.liang@linux.intel.com> wrote:
> Performance impact:
> The processing time may increase with the LBR stitching approach
> enabled. The impact depends on the number of samples with stitched LBRs.
>
> For sqlite's tcltest,
> perf record --call-graph lbr -- make tcltest
> perf report --stitch-lbr
>
> There are 4.11% samples has stitched LBRs.
> Total number of samples: 2833728
> The number of samples with stitched LBRs 116478
>
> The processing time of perf report increases 6.8%
> Without --stitch-lbr: 55906106 usec
> With --stitch-lbr: 59728701 usec
>
> For a simple test case tchain_edit with 43 depth of call stacks.
> perf record --call-graph lbr -- ./tchain_edit
> perf report --stitch-lbr
>
> There are 99.9% samples has stitched LBRs.
> Total number of samples: 10915
> The number of samples with stitched LBRs 10905
>
> The processing time of perf report increases 67.4%
> Without --stitch-lbr: 11970508 usec
> With --stitch-lbr: 20036055 usec
That cost seems pretty high, while the feature sounds useful - is there
any way to speed this up?
Thanks,
Ingo
next prev parent reply other threads:[~2019-10-07 18:24 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-10-07 17:59 [PATCH 00/10] Stitch LBR call stack kan.liang
2019-10-07 17:59 ` [PATCH 01/10] perf/core, x86: Add PERF_SAMPLE_LBR_TOS kan.liang
2019-10-08 8:31 ` Peter Zijlstra
2019-10-08 13:53 ` Liang, Kan
2019-10-08 14:38 ` Peter Zijlstra
2019-10-08 15:25 ` Liang, Kan
2019-10-08 16:32 ` Peter Zijlstra
2019-10-07 17:59 ` [PATCH 02/10] perf tools: Support PERF_SAMPLE_LBR_TOS kan.liang
2019-10-07 17:59 ` [PATCH 03/10] perf pmu: Add support for PMU capabilities kan.liang
2019-10-07 17:59 ` [PATCH 04/10] perf header: Support CPU " kan.liang
2019-10-07 17:59 ` [PATCH 05/10] perf machine: Refine the function for LBR call stack reconstruction kan.liang
2019-10-07 17:59 ` [PATCH 06/10] perf tools: Stitch LBR call stack kan.liang
2019-10-07 17:59 ` [PATCH 07/10] perf report: Add option to enable the LBR stitching approach kan.liang
2019-10-07 17:59 ` [PATCH 08/10] perf script: " kan.liang
2019-10-07 17:59 ` [PATCH 09/10] perf top: " kan.liang
2019-10-07 17:59 ` [PATCH 10/10] perf c2c: " kan.liang
2019-10-07 18:24 ` Ingo Molnar [this message]
2019-10-07 20:06 ` [PATCH 00/10] Stitch LBR call stack Liang, Kan
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