Re: [PATCH v6 09/16] sched/cpufreq: uclamp: Add utilization clamping for RT tasks

Patrick Bellasi
2019-01-24T16:05:18Z

On 24-Jan 16:15, Peter Zijlstra wrote:
> On Tue, Jan 15, 2019 at 10:15:06AM +0000, Patrick Bellasi wrote:
> > Add uclamp_default_perf, a special set of clamp values to be used
> > for tasks requiring maximum performance, i.e. by default all the non
> > clamped RT tasks.
>
> Urgh... why though?

Because tasks without a task-specific clamp value assigned are subject
to system default... but those, by default, don't clamp at all:

uclamp_default = [0..1024]

For RT tasks however, we want to execute then always at max OPP, if
not otherwise requested (e.g. task-specific value). Thus we need a
different set of default clamps:

uclamp_perf_default = [1024..1024]

--
#include <best/regards.h>

Patrick Bellasi