From: Viresh Kumar <viresh.kumar@linaro.org>
To: Stratos Karafotis <stratosk@semaphore.gr>
Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>,
"Srivatsa S. Bhat" <srivatsa.bhat@linux.vnet.ibm.com>,
"linux-pm@vger.kernel.org" <linux-pm@vger.kernel.org>,
LKML <linux-kernel@vger.kernel.org>
Subject: Re: [RFC][PATCH] cpufreq: governor: Change the calculation of load for deferred updates
Date: Fri, 18 Nov 2016 08:45:05 +0530 [thread overview]
Message-ID: <20161118031504.GC3110@vireshk-i7> (raw)
In-Reply-To: <4f7f7d9e-4b6b-a9f8-bf54-a6d99bd952c6@semaphore.gr>
On 17-11-16, 21:54, Stratos Karafotis wrote:
> Commit 18b46abd0009 ("cpufreq: governor: Be friendly towards latency-
> sensitive bursty workloads"), introduced a method to copy the calculated
> load from the previous sampling period in case of a deferred timer
> (update).
>
> This helps on bursty workloads but generally coping the load for the
> previous measurement could be arbitrary, because of the possibly different
> nature of the new workload.
>
> Instead of coping the load from the previous period we can calculate the
> load considering that between the two samples, the busy time is comparable
> to one sampling period. Thus:
>
> busy = time_elapsed - idle_time
>
> and
>
> load = 100 * busy / sampling_rate;
>
> Also, remove the 'unlikely' hint because it seems that a deferred update
> is a very common case on most modern systems.
You have any numbers to prove that this improves something ?
--
viresh
prev parent reply other threads:[~2016-11-18 3:21 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-11-17 19:54 [RFC][PATCH] cpufreq: governor: Change the calculation of load for deferred updates Stratos Karafotis
2016-11-18 3:15 ` Viresh Kumar [this message]
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