Date: Wed, 18 Nov 2015 15:09:44 +0000
From: Morten Rasmussen <morten.rasmussen@arm.com>
To: Jacob Pan <jacob.jun.pan@linux.intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>, Ingo Molnar <mingo@kernel.org>,
        Ingo Molnar <mingo@redhat.com>, Thomas Gleixner <tglx@linutronix.de>,
        John Stultz <john.stultz@linaro.org>,
        LKML <linux-kernel@vger.kernel.org>,
        Arjan van de Ven <arjan@linux.intel.com>,
        Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>,
        Len Brown <len.brown@intel.com>,
        Rafael Wysocki <rafael.j.wysocki@intel.com>,
        Eduardo Valentin <edubezval@gmail.com>, Paul Turner <pjt@google.com>
Subject: Re: [PATCH 3/4] sched: introduce synchronized idle injection
Message-ID: <20151118150944.GC30184@e105550-lin.cambridge.arm.com>
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On Wed, Nov 18, 2015 at 06:52:33AM -0800, Jacob Pan wrote:
> On Wed, 18 Nov 2015 14:04:41 +0000
> Morten Rasmussen <morten.rasmussen@arm.com> wrote:
> 
> > Then I'm confused :-/
> > 
> > I see the hrtimers, but the actual idle duration appears to be in
> > ticks rather than ms and then converted later.
> > 
> > +/* Duration of idle time in ticks of each injection period
> > */ +unsigned int sysctl_sched_cfs_idle_inject_duration = 5UL;
> > 
> > ...and futher down we have:
> > 
> > +       duration_msec =
> > jiffies_to_msecs(sysctl_sched_cfs_idle_inject_duration);
> I used hrtimers but still round around tick boundaries of ktime.
> It is more reliable than jiffies in terms of getting timely updates.

Okay. But it does mean that the defeault idle period is 5 ticks (50ms @
HZ=100) and not 5 ms.
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