From: "Rafael J. Wysocki" <rafael@kernel.org>
To: Julia Lawall <julia.lawall@inria.fr>
Cc: Francisco Jerez <currojerez@riseup.net>,
"Rafael J. Wysocki" <rafael@kernel.org>,
Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>,
Len Brown <lenb@kernel.org>,
Viresh Kumar <viresh.kumar@linaro.org>,
Linux PM <linux-pm@vger.kernel.org>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Ingo Molnar <mingo@redhat.com>,
Peter Zijlstra <peterz@infradead.org>,
Juri Lelli <juri.lelli@redhat.com>,
Vincent Guittot <vincent.guittot@linaro.org>
Subject: Re: cpufreq: intel_pstate: map utilization into the pstate range
Date: Tue, 28 Dec 2021 18:40:18 +0100 [thread overview]
Message-ID: <CAJZ5v0i4xnesG=vfx7Y-wyeaGvjDeGcsaOVqhRLnV8YXk-m2gA@mail.gmail.com> (raw)
In-Reply-To: <alpine.DEB.2.22.394.2112281745240.24929@hadrien>
On Tue, Dec 28, 2021 at 5:58 PM Julia Lawall <julia.lawall@inria.fr> wrote:
>
> I looked a bit more into why pstate 20 is always using the least energy. I
> have just one thread spinning for 10 seconds, I use a fixed value for the
> pstate, and I measure the energy usage with turbostat.
How exactly do you fix the pstate?
> I tried this on a
> 2-socket Intel 6130 and a 4-socket Intel 6130. The experiment runs 40
> times.
>
> There seem to be only two levels of CPU energy usage. On the 2-socket
> machine the energy usage is around 600J up to pstate 20 and around 1000J
> after that. On the 4-socket machine it is twice that.
These are the package power numbers from turbostat, aren't they?
> The change in RAM energy usage is similar, eg around 320J for the 2-socket
> machine up to pstate 20, and around 460J for higher pstates.
>
> On the 6130, pstate 21 is 2.1GHz, which is the nominal frequency of the
> machine. So it seems that the most efficient thing is to be just below
> that. The reduced execution time with pstate 20 as compared to pstate 10
> greatly outweighs any small increase in the energy usage due to changing
> the frequency.
>
> Perhaps there is something abnormal in how the machines are configured?
next prev parent reply other threads:[~2021-12-28 17:40 UTC|newest]
Thread overview: 53+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-12-13 22:52 cpufreq: intel_pstate: map utilization into the pstate range Julia Lawall
2021-12-17 18:36 ` Rafael J. Wysocki
2021-12-17 19:32 ` Julia Lawall
2021-12-17 20:36 ` Francisco Jerez
2021-12-17 22:51 ` Julia Lawall
2021-12-18 0:04 ` Francisco Jerez
2021-12-18 6:12 ` Julia Lawall
2021-12-18 10:19 ` Francisco Jerez
2021-12-18 11:07 ` Julia Lawall
2021-12-18 22:12 ` Francisco Jerez
2021-12-19 6:42 ` Julia Lawall
2021-12-19 14:19 ` Rafael J. Wysocki
2021-12-19 14:30 ` Rafael J. Wysocki
2021-12-19 21:47 ` Julia Lawall
2021-12-19 22:10 ` Francisco Jerez
2021-12-19 22:41 ` Julia Lawall
2021-12-19 23:31 ` Francisco Jerez
2021-12-21 17:04 ` Rafael J. Wysocki
2021-12-21 23:56 ` Francisco Jerez
2021-12-22 14:54 ` Rafael J. Wysocki
2021-12-24 11:08 ` Julia Lawall
2021-12-28 16:58 ` Julia Lawall
2021-12-28 17:40 ` Rafael J. Wysocki [this message]
2021-12-28 17:46 ` Julia Lawall
2021-12-28 18:06 ` Rafael J. Wysocki
2021-12-28 18:16 ` Julia Lawall
2021-12-29 9:13 ` Julia Lawall
2021-12-30 17:03 ` Rafael J. Wysocki
2021-12-30 17:54 ` Julia Lawall
2021-12-30 17:58 ` Rafael J. Wysocki
2021-12-30 18:20 ` Julia Lawall
2021-12-30 18:37 ` Rafael J. Wysocki
2021-12-30 18:44 ` Julia Lawall
2022-01-03 15:50 ` Rafael J. Wysocki
2022-01-03 16:41 ` Julia Lawall
2022-01-03 18:23 ` Julia Lawall
2022-01-03 19:58 ` Rafael J. Wysocki
2022-01-03 20:51 ` Julia Lawall
2022-01-04 14:09 ` Rafael J. Wysocki
2022-01-04 15:49 ` Julia Lawall
2022-01-04 19:22 ` Rafael J. Wysocki
2022-01-05 20:19 ` Julia Lawall
2022-01-05 23:46 ` Francisco Jerez
2022-01-06 19:49 ` Julia Lawall
2022-01-06 20:28 ` Srinivas Pandruvada
2022-01-06 20:43 ` Julia Lawall
2022-01-06 21:55 ` srinivas pandruvada
2022-01-06 21:58 ` Julia Lawall
2022-01-05 0:38 ` Francisco Jerez
2021-12-19 14:14 ` Rafael J. Wysocki
2021-12-19 17:03 ` Julia Lawall
2021-12-19 22:30 ` Francisco Jerez
2021-12-21 18:10 ` Rafael J. Wysocki
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