lkml.org 
[lkml]   [2016]   [May]   [19]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
SubjectRe: [PATCH 5/5] cpufreq: schedutil: do not update rate limit ts when freq is unchanged
From
On Fri, May 20, 2016 at 2:24 AM, Rafael J. Wysocki <rafael@kernel.org> wrote:
> On Fri, May 20, 2016 at 1:34 AM, Steve Muckle <steve.muckle@linaro.org> wrote:
>> On Thu, May 19, 2016 at 11:15:52PM +0200, Rafael J. Wysocki wrote:
>>> But anyway this change again seems to be an optimization that might be
>>> done later to me.
>>>
>>> I guess there are many things that might be optimized in schedutil,
>>> but I'd prefer to address one item at a time, maybe going after the
>>> ones that appear most relevant first?
>>
>> Calling the last two patches in this series optimizations is a stretch
>> IMO. Issuing frequency change requests that result in the same
>> target-supported frequency is clearly unnecessary and ends up delaying
>> more urgent frequency changes, which I think is more like a bug.
>
> The [4/5] is pulling stuff where it doesn't belong. Simple as that.
> Frequency tables don't belong in schedutil, so don't pull them in
> there.
>
> If you want to do that cleanly, add a call to the driver that will
> tell you what frequency would be selected by it if it were given a
> particular target.

Also I think that it would be good to avoid walking the frequency
table twice in case we end up wanting to update the frequency after
all. With the [4/5] we'd do it once in get_next_freq() and then once
more in cpufreq_driver_fast_switch(), for example, and walking the
frequency table may be more expensive that doing the switch in the
first place.

\
 
 \ /
  Last update: 2016-05-20 03:01    [W:0.198 / U:0.116 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site