lkml.org 
[lkml]   [2016]   [Feb]   [19]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
SubjectRe: [PATCH v10 1/3] cpufreq: Add mechanism for registering utilization update callbacks
From
Date
On Fri, 2016-02-19 at 08:09 +0000, Juri Lelli wrote:
Hi Juri,
> > 
> Hi Rafael,
>
> On 18/02/16 21:22, Rafael J. Wysocki wrote:
> > On Mon, Feb 15, 2016 at 10:47 PM, Rafael J. Wysocki <rjw@rjwysocki.
> > net> wrote:
> > > From: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
> > >
>
[...]

> However, I still don't quite get why we want to introduce an
> interface
> for explicit passing of util and max if we are not using such
> parameters
> yet. Also, I couldn't find any indication of how such parameters will
> be
> used in the future. If what we need today is a periodic kick for
> cpufreq
> governors that need it, we should simply do how we already do for RT
> and
> DL, IMHO. Also because the places where the current hooks reside
> might
> not be the correct and useful one once we'll start using the
> utilization
> parameters. I could probably make a case for DL where we should place
> hooks in admission control path (or somewhere else when more
> sophisticated mechanisms we'll be in place) rather then in the
> periodic
> tick.
We did experiments using util/max in intel_pstate. For some benchmarks
there were regression of 4 to 5%, for some benchmarks it performed at
par with getting utilization from the processor. Further optimization
in the algorithm is possible and still in progress. Idea is that we can
change P-State fast enough and be more reactive. Once I have good data,
I will send to this list. The algorithm can be part of the cpufreq
governor too.

Thanks,
Srinivas


\
 
 \ /
  Last update: 2016-02-19 18:01    [W:0.265 / U:0.096 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site