From: Peter Zijlstra <peterz@infradead.org>
To: Clemens Ladisch <clemens@ladisch.de>
Cc: Thomas Gleixner <tglx@linutronix.de>,
Stefan Richter <stefanr@s5r6.in-berlin.de>,
linux-kernel@vger.kernel.org,
linux1394-devel@lists.sourceforge.net,
John Stultz <john.stultz@linaro.org>
Subject: Re: firewire: CLOCK_MONOTONIC_RAW exposure
Date: Wed, 16 Jul 2014 14:37:27 +0200 [thread overview]
Message-ID: <20140716123727.GA19379@twins.programming.kicks-ass.net> (raw)
In-Reply-To: <53C6633D.9080905@ladisch.de>
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On Wed, Jul 16, 2014 at 01:34:21PM +0200, Clemens Ladisch wrote:
> Thomas Gleixner wrote:
> > I wonder why firewire exposed CLOCK_MONOTONIC_RAW to user space.
> >
> > What's the purpose of that? CLOCK_MONOTONIC_RAW is the raw time based
> > on the initial frequency setup of the clocksource. That can be quite
> > off from the NTP corrected frequency which is exposed by
> > CLOCK_MONOTONIC.
>
> The purpose is to get a stable clock, i.e., to avoid clock rate changes
> caused by NTP corrections.
That's maybe half an answer; what do you need that for?
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next prev parent reply other threads:[~2014-07-16 12:37 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-07-16 9:57 firewire: CLOCK_MONOTONIC_RAW exposure Thomas Gleixner
2014-07-16 11:34 ` Clemens Ladisch
2014-07-16 12:37 ` Peter Zijlstra [this message]
2014-07-16 14:16 ` Clemens Ladisch
2014-07-16 15:00 ` Mark Brown
2014-07-17 8:37 ` Daniel Thompson
2014-07-17 13:19 ` Thomas Gleixner
2014-07-17 16:14 ` John Stultz
2014-07-17 16:34 ` Daniel Thompson
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