Messages in this thread | | | Date | Mon, 7 Oct 2019 20:24:35 +0200 | From | Ingo Molnar <> | Subject | Re: [PATCH 00/10] Stitch LBR call stack |
| |
* 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
| |