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Date: Tue, 10 Nov 2015 15:58:23 +0100
From: Peter Zijlstra <peterz@infradead.org>
To: Jacob Pan <jacob.jun.pan@linux.intel.com>
Cc: LKML <linux-kernel@vger.kernel.org>,
        Rafael Wysocki <rafael.j.wysocki@intel.com>,
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        Punit Agrawal <punit.agrawal@arm.com>,
        Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Subject: Re: [RFC PATCH v2 3/3] sched: introduce synchronized idle injection
Message-ID: <20151110145823.GD17308@twins.programming.kicks-ass.net>
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On Tue, Nov 10, 2015 at 06:01:16AM -0800, Jacob Pan wrote:
> On Tue, 10 Nov 2015 14:23:24 +0100
> Peter Zijlstra <peterz@infradead.org> wrote:

> > It looks like what you want is:
> > 
> > 	hrtimer_forward(hrt, period);
> > 
> > unconditionally.

> In the ideal world yes. But my thinking was that timers may not be so
> accurate to deliver interrupts, over the time the timeout error may
> accumulate so that eventually timers will be out of sync.

Timers have a global time base. Even if individual deliveries have an
error, there is no accumulated error.