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From: sboyd@codeaurora.org (Stephen Boyd)
To: linux-arm-kernel@lists.infradead.org
Subject: Weird sched_clock behaviour during boot with -rc1
Date: Fri, 7 Feb 2014 11:37:39 -0800	[thread overview]
Message-ID: <20140207193739.GC12815@codeaurora.org> (raw)
In-Reply-To: <52F524A3.3070400@linaro.org>

On 02/07, John Stultz wrote:
> On 02/04/2014 02:00 PM, Stephen Boyd wrote:
> >>
> > That would work, but why can't we just hold the write seqlock
> > during the registration? We would need to make a lockeless
> > version of update_sched_clock() but that doesn't look too hard.
> > It might actually turn out nicer because we call
> > update_sched_clock() here just to set the epoch_cyc but we have
> > to reset the epoch_ns back to 0 to start the count off right.
> >
> > How about this? The only concern is calling read_sched_clock()
> > inside the seqlock, but I don't think that's a concern and if it
> > is we can call it outside the lock at the beginning of this
> > function.
> 
> So whats the story here? Are we waiting on an ack from Will or would you
> rather go with Josh's approach?

An acked-by/tested-by from Will would be good. I'll cook up a
patch right now to do everything that has been mentioned in this
thread.

-- 
Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum,
hosted by The Linux Foundation

  reply	other threads:[~2014-02-07 19:37 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-02-04 18:36 Weird sched_clock behaviour during boot with -rc1 Will Deacon
2014-02-04 20:46 ` John Stultz
2014-02-04 22:00   ` Stephen Boyd
2014-02-05 21:47     ` Josh Cartwright
2014-02-07 18:23     ` John Stultz
2014-02-07 19:37       ` Stephen Boyd [this message]
2014-02-07 20:48       ` [PATCH] sched_clock: Prevent callers from seeing half-updated data Stephen Boyd
2014-02-07 22:22         ` Stephen Boyd
2014-02-07 22:28           ` John Stultz
2014-02-11  6:49             ` Stephen Boyd
2014-02-17 18:13               ` John Stultz
2014-02-07 22:28         ` [PATCH v2] " Stephen Boyd
2014-02-10 11:14           ` Will Deacon
2014-02-17 11:19             ` Will Deacon
2014-02-17 18:04               ` John Stultz

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