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From: Peter Zijlstra <peterz@infradead.org>
To: Joel Fernandes <joelaf@google.com>
Cc: linux-pm@vger.kernel.org, linux-kernel@vger.kernel.org,
	Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>,
	Len Brown <lenb@kernel.org>,
	"Rafael J . Wysocki" <rjw@rjwysocki.net>,
	Viresh Kumar <viresh.kumar@linaro.org>,
	Ingo Molnar <mingo@redhat.com>
Subject: Re: [PATCH v2 1/2] cpufreq: Make iowait boost a policy option
Date: Fri, 19 May 2017 11:42:45 +0200	[thread overview]
Message-ID: <20170519094245.ztm6tt2iwkaiwsya@hirez.programming.kicks-ass.net> (raw)
In-Reply-To: <20170519062344.27692-2-joelaf@google.com>

On Thu, May 18, 2017 at 11:23:43PM -0700, Joel Fernandes wrote:
> Make iowait boost a cpufreq policy option and enable it for intel_pstate
> cpufreq driver. Governors like schedutil can use it to determine if
> boosting for tasks that wake up with p->in_iowait set is needed.

Rather than just flat out disabling the option, is there something
better we can do on ARM?

The reason for the IO-wait boost is to ensure we feed our external
devices data ASAP, this reduces wait times, increases throughput and
decreases the duration the devices have to operate.

I realize max freq/volt might not be the best option for you, but is
there another spot that would make sense? I can imagine you want to
return your MMC to low power state ASAP as well.


So rather than a disable flag, I would really rather see an IO-wait OPP
state selector or something.

  reply	other threads:[~2017-05-19  9:42 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-05-19  6:23 [PATCH v2 0/2] Make iowait_boost optional and default to policy Joel Fernandes
2017-05-19  6:23 ` [PATCH v2 1/2] cpufreq: Make iowait boost a policy option Joel Fernandes
2017-05-19  9:42   ` Peter Zijlstra [this message]
2017-05-19 10:21     ` Peter Zijlstra
2017-05-19 17:04     ` Joel Fernandes
2017-05-22  8:21       ` Peter Zijlstra
2017-05-24 20:17         ` Joel Fernandes
2017-06-10  8:08           ` Joel Fernandes
2017-06-10 13:56             ` Peter Zijlstra
2017-06-11  6:59               ` Joel Fernandes
2017-05-19  6:23 ` [PATCH v2 2/2] sched: Make iowait_boost optional in schedutil Joel Fernandes
2017-05-19  6:50   ` Viresh Kumar
2017-05-19 16:10     ` Joel Fernandes
2017-07-11 19:02       ` Saravana Kannan

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