On 14 May 2018 at 18:48, Patrick Bellasi <[email protected]> wrote: > On 14-May 11:16, Vincent Guittot wrote: >> Hi Patrick, > > Hi Vincent, > >> On 11 May 2018 at 15:15, Patrick Bellasi <[email protected]> wrote: >> > Since the refactoring introduced by: >> > >> > commit 8f111bc357aa ("cpufreq/schedutil: Rewrite CPUFREQ_RT support") >> > >> > we aggregate FAIR utilization only if this class has runnable tasks. >> > This was mainly due to avoid the risk to stay on an high frequency just >> > because of the blocked utilization of a CPU not being properly decayed >> > while the CPU was idle. >> > >> > However, since: >> > >> > commit 31e77c93e432 ("sched/fair: Update blocked load when newly idle") >> > >> > the FAIR blocked utilization is properly decayed also for IDLE CPUs. >> > >> > This allows us to use the FAIR blocked utilization as a safe mechanism >> > to gracefully reduce the frequency only if no FAIR tasks show up on a >> > CPU for a reasonable period of time. >> > >> > Moreover, we also reduce the frequency drops of CPUs running periodic >> > tasks which, depending on the task periodicity and the time required >> > for a frequency switch, was increasing the chances to introduce some >> > undesirable performance variations. >> > >> > Reported-by: Vincent Guittot <[email protected]> >> > Signed-off-by: Patrick Bellasi <[email protected]> >> > Acked-by: Viresh Kumar <[email protected]> >> > Cc: Ingo Molnar <[email protected]> >> > Cc: Peter Zijlstra <[email protected]> >> > Cc: Rafael J. Wysocki <[email protected]> >> > Cc: Vincent Guittot <[email protected]> >> > Cc: Viresh Kumar <[email protected]> >> > Cc: Joel Fernandes <[email protected]> >> > Cc: [email protected] >> > Cc: [email protected] >> >> With this patch, I can't see the spurious OPP changes that I was seeing >> before > > Cool thanks... regarding OPP updates I've added some more comments in > my reply to Joel's comments to my last patch of this series. > > Would be nice if you can have a look... toward the end there are some > considerations about schedutil updates (indirectly) triggered by your > patches for blocked load updates on IDLE CPUs.
I have started to have a look at the 3rd patch and was checking if there were some hole and your proposal regarding the update of blocked load and the removed utilization I will read your latest comment. > >> FWIW >> Acked-by: Vincent Guittot <[email protected]> >> Tested-by: Vincent Guittot <[email protected]> > > Thanks for testing, will add these to the next respin. > > -- > #include <best/regards.h> > > Patrick Bellasi
