From: John Stultz <johnstul@us.ibm.com>
To: Thomas Gleixner <tglx@linutronix.de>
Cc: Tim Ricketts <tr@earth.li>, Michael Smith <msmith@xiph.org>,
LKML <linux-kernel@vger.kernel.org>,
Andy Wingo <wingo@fluendo.com>, Ingo Molnar <mingo@elte.hu>
Subject: Re: gettimeofday() jumping into the future
Date: Mon, 31 Mar 2008 09:03:27 -0700 [thread overview]
Message-ID: <1206979407.6175.2.camel@jstultz-laptop> (raw)
In-Reply-To: <alpine.LFD.1.10.0803311048170.3219@apollo.tec.linutronix.de>
On Mon, 2008-03-31 at 10:55 +0200, Thomas Gleixner wrote:
>
> > + if (cycle_now < clock->cycle_last)
> > + return 0;
> > +
>
> No, this breaks wrapping clocksources e.g. pmtimer. We need a
> different sanity check for that TSC crap.
Yea. If you're going to do that sort of logic (which requires a costly
cmpxchg as well), it should be done in the read() function of the
clocksource.
thanks
-john
next prev parent reply other threads:[~2008-03-31 16:03 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-08-23 11:08 gettimeofday() jumping into the future Michael Smith
2007-08-23 11:36 ` Gerald Britton
2007-08-23 13:03 ` Avi Kivity
2007-08-23 20:09 ` H. Peter Anvin
2007-08-23 20:07 ` H. Peter Anvin
2007-08-23 11:47 ` Peter Zijlstra
2007-08-23 12:20 ` Michael Smith
2007-08-23 18:47 ` john stultz
2007-08-25 16:44 ` Michael Smith
2008-03-30 21:17 ` Tim Ricketts
2008-03-31 7:18 ` Andi Kleen
2008-04-03 11:47 ` James Courtier-Dutton
2008-04-03 12:22 ` James Courtier-Dutton
2008-04-03 12:44 ` James Courtier-Dutton
2008-04-11 23:11 ` john stultz
2008-03-31 8:55 ` Thomas Gleixner
2008-03-31 16:03 ` John Stultz [this message]
2008-04-02 11:22 ` Thomas Gleixner
2008-04-02 23:57 ` Karsten Wiese
2008-04-03 6:28 ` Thomas Gleixner
2008-04-02 4:26 ` Mihai Donțu
2008-04-02 4:27 ` Mihai Donțu
[not found] <47F3F313.7030803@vmware.com>
2008-04-02 22:40 ` Tim Mann
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