Messages in this thread | | | From | "Rafael J. Wysocki" <> | Subject | Re: [PATCH v7 1/2] cpufreq: schedutil: Make iowait boost more energy efficient | Date | Fri, 28 Jul 2017 01:54:41 +0200 |
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On Monday, July 24, 2017 11:37:58 AM Joel Fernandes wrote: > On Mon, Jul 24, 2017 at 1:57 AM, Viresh Kumar <viresh.kumar@linaro.org> wrote: > > On 23-07-17, 08:54, Joel Fernandes wrote: > >> Currently the iowait_boost feature in schedutil makes the frequency go to max > >> on iowait wakeups. This feature was added to handle a case that Peter > >> described where the throughput of operations involving continuous I/O requests > >> [1] is reduced due to running at a lower frequency, however the lower > >> throughput itself causes utilization to be low and hence causing frequency to > >> be low hence its "stuck". > >> > >> Instead of going to max, its also possible to achieve the same effect by > >> ramping up to max if there are repeated in_iowait wakeups happening. This patch > >> is an attempt to do that. We start from a lower frequency (policy->min) > >> and double the boost for every consecutive iowait update until we reach the > >> maximum iowait boost frequency (iowait_boost_max). > >> > >> I ran a synthetic test (continuous O_DIRECT writes in a loop) on an x86 machine > >> with intel_pstate in passive mode using schedutil. In this test the iowait_boost > >> value ramped from 800MHz to 4GHz in 60ms. The patch achieves the desired improved > >> throughput as the existing behavior. > >> > >> [1] https://patchwork.kernel.org/patch/9735885/ > >> > >> Cc: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com> > >> Cc: Len Brown <lenb@kernel.org> > >> Cc: Rafael J. Wysocki <rjw@rjwysocki.net> > >> Cc: Viresh Kumar <viresh.kumar@linaro.org> > >> Cc: Ingo Molnar <mingo@redhat.com> > >> Cc: Peter Zijlstra <peterz@infradead.org> > >> Suggested-by: Peter Zijlstra <peterz@infradead.org> > >> Suggested-by: Viresh Kumar <viresh.kumar@linaro.org> > >> Signed-off-by: Joel Fernandes <joelaf@google.com> > >> --- > >> kernel/sched/cpufreq_schedutil.c | 38 ++++++++++++++++++++++++++++++++------ > >> 1 file changed, 32 insertions(+), 6 deletions(-) > > > > You Send V7 [1-2]/2 twice, Are they different ? > > No they are the same. Rafael suggested reposting it with linux-pm in > CC I just resent it. > > > > > For both the patches: > > > > Acked-by: Viresh Kumar <viresh.kumar@linaro.org> > > Thanks!
Applied, thanks!
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