From: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
To: Eero Tamminen <eero.t.tamminen@intel.com>,
lenb@kernel.org, rjw@rjwysocki.net, viresh.kumar@linaro.org
Cc: mgorman@techsingularity.net, currojerez@riseup.net,
ggherdovich@suse.cz, peterz@infradead.org,
linux-pm@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] cpufreq: intel_pstate: Optimize IO boost in non HWP mode
Date: Mon, 03 Sep 2018 08:15:31 -0700 [thread overview]
Message-ID: <9d2882f2877e52c611362dc7e3699eca1e715695.camel@linux.intel.com> (raw)
In-Reply-To: <1244c5d6-460e-0e0b-b7bf-a46e73327383@intel.com>
On Mon, 2018-09-03 at 18:10 +0300, Eero Tamminen wrote:
> Hi,
>
> On 31.08.2018 20:28, Srinivas Pandruvada wrote:
> ...
> > As per testing Eero Tamminen, the results are comparable to the
> > patchset
> > https://patchwork.kernel.org/patch/10312259/
> > But he has to watch results for several days to check trend.
>
> It's close, but there is some gap compared to Francisco's version.
>
> (Because of the large variance on TDP limited devices, and factors
> causing extra perf differences e.g. between boots, it's hard to give
> exact number without having trends from several days / weeks. I
> would
> also need new version of Fransisco's patch set that applies to
> latest
> kernel like yours does.)
>
>
> > Since here boost is getting limited to turbo and non turbo, we need
> > some
> > ways to adjust the fractions corresponding to max non turbo as
> > well. It
> > is much easier to use the actual P-state limits for boost instead
> > of
> > fractions. So here P-state io boost limit is applied on top of the
> > P-state limit calculated via current algorithm by removing current
> > io_wait boost calculation using fractions.
> >
> > Since we prefer to use common algorithm for all processor
> > platforms, this
> > change was tested on other client and sever platforms as well. All
> > results
> > were within the margin of errors. Results:
> > https://bugzilla.kernel.org/attachment.cgi?id=278149
>
> Good.
>
> Francisco, how well the listed PTS tests cover latency bound cases
> you
> were concerned about? [1]
>
>
> - Eero
>
> [1] Fransisco was concerned that the patch:
> * trade-off might regress latency bound cases (which I haven't
> tested, I
> tested only 3D throughput), and
> * that it addressed only other of the sources of energy
> inefficiencies
> he had identified (which could explain slightly better 3D results
> from
> his more complex patch set).
It is always possible to submit improvement patch later. Atleast this
patch will reduce the usage of turbo.
Thanks,
Srinivas
next prev parent reply other threads:[~2018-09-03 15:15 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-08-31 17:28 [PATCH] cpufreq: intel_pstate: Optimize IO boost in non HWP mode Srinivas Pandruvada
2018-09-03 15:10 ` Eero Tamminen
2018-09-03 15:15 ` Srinivas Pandruvada [this message]
2018-09-04 6:53 ` Francisco Jerez
2018-09-04 17:50 ` Srinivas Pandruvada
2018-09-05 1:37 ` Francisco Jerez
2018-09-05 5:59 ` Srinivas Pandruvada
2018-09-06 4:20 ` Francisco Jerez
2018-09-11 11:21 ` Rafael J. Wysocki
2018-09-11 17:35 ` Francisco Jerez
2018-09-14 8:58 ` Rafael J. Wysocki
2018-09-15 6:34 ` Francisco Jerez
2018-09-17 9:07 ` Rafael J. Wysocki
2018-09-17 21:23 ` Francisco Jerez
2018-09-11 10:29 ` Rafael J. Wysocki
2018-09-11 10:28 ` Rafael J. Wysocki
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