Messages in this thread | | | From | "Ghannam, Yazen" <> | Subject | RE: [PATCH] tools/power turbostat: Make interval calculation per thread to reduce jitter | Date | Fri, 7 Jun 2019 16:28:07 +0000 |
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> -----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
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