lkml.org 
[lkml]   [2019]   [Aug]   [31]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    /
    From
    Date
    SubjectRe: [PATCH] tools/power turbostat: Make interval calculation per thread to reduce jitter
    Yeah, I like this patch, and I have applied it.

    thanks!
    -Len

    On Fri, Jun 7, 2019 at 12:28 PM Ghannam, Yazen <Yazen.Ghannam@amd.com> wrote:
    >
    > > -----Original Message-----
    > > From: Ghannam, Yazen <Yazen.Ghannam@amd.com>
    > > Sent: Tuesday, April 23, 2019 12:53 PM
    > > To: Ghannam, Yazen <Yazen.Ghannam@amd.com>; linux-pm@vger.kernel.org; len.brown@intel.com
    > > Cc: linux-kernel@vger.kernel.org; Len Brown <lenb@kernel.org>
    > > Subject: RE: [PATCH] tools/power turbostat: Make interval calculation per thread to reduce jitter
    > >
    > > > -----Original Message-----
    > > > From: linux-kernel-owner@vger.kernel.org <linux-kernel-owner@vger.kernel.org> On Behalf Of Ghannam, Yazen
    > > > Sent: Monday, March 25, 2019 12:33 PM
    > > > To: linux-pm@vger.kernel.org
    > > > Cc: Ghannam, Yazen <Yazen.Ghannam@amd.com>; linux-kernel@vger.kernel.org; lenb@kernel.org
    > > > Subject: [PATCH] tools/power turbostat: Make interval calculation per thread to reduce jitter
    > > >
    > > > From: Yazen Ghannam <yazen.ghannam@amd.com>
    > > >
    > > > Turbostat currently normalizes TSC and other values by dividing by an
    > > > interval. This interval is the delta between the start of one global
    > > > (all counters on all CPUs) sampling and the start of another. However,
    > > > this introduces a lot of jitter into the data.
    > > >
    > > > In order to reduce jitter, the interval calculation should be based on
    > > > timestamps taken per thread and close to the start of the thread's
    > > > sampling.
    > > >
    > > > Define a per thread time value to hold the delta between samples taken
    > > > on the thread.
    > > >
    > > > Use the timestamp taken at the beginning of sampling to calculate the
    > > > delta.
    > > >
    > > > Move the thread's beginning timestamp to after the CPU migration to
    > > > avoid jitter due to the migration.
    > > >
    > > > Use the global time delta for the average time delta.
    > > >
    > > > Signed-off-by: Yazen Ghannam <yazen.ghannam@amd.com>
    > > > ---
    > >
    > > Hi Len,
    > >
    > > Any comments on this patch?
    > >
    >
    > Hi Len,
    >
    > Just wanted to check in. Do you have any comments on this patch?
    >
    > Thanks,
    > Yazen



    --
    Len Brown, Intel Open Source Technology Center

    \
     
     \ /
      Last update: 2019-08-31 18:49    [W:3.727 / U:0.240 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site