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From: jbarnes@sgi.com (Jesse Barnes)
To: linux-ia64@vger.kernel.org
Subject: Re: [PATCH] do_gettimeofday() fails to compensate for lost ticks
Date: Wed, 24 Sep 2003 18:21:51 +0000	[thread overview]
Message-ID: <marc-linux-ia64-106442775500799@msgid-missing> (raw)
In-Reply-To: <marc-linux-ia64-106442430128845@msgid-missing>

On Wed, Sep 24, 2003 at 12:17:41PM -0600, Khalid Aziz wrote:
> > This explanation doesn't sound right.  See the "lost" variable in
> > gettimeoffset().  It's supposed to account for lost ticks.
> > 
> >         --david
> 
> David,
> 
> So it would seem. What would then explain clock going backwards? Here is
> what I see when the test fails:
> 
> tpget\x1037128357,995121000, tpset\x1037128358,0
> 
> where tpget is what was returned by gettimeofday() and tpset is what was
> set by settimeofday(). Clock seems to have moved back by 4.879 msec.

Just FYI, Martin Hicks noticed recently that 2.6 on a machine with itc
drift also has this problem.  I think John Hawkes has some ideas on how
to fix it, but I haven't had time to look at it yet.

Thanks,
Jesse

  parent reply	other threads:[~2003-09-24 18:21 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2003-09-24 17:21 [PATCH] do_gettimeofday() fails to compensate for lost ticks Khalid Aziz
2003-09-24 18:02 ` David Mosberger
2003-09-24 18:17 ` Khalid Aziz
2003-09-24 18:21 ` Jesse Barnes [this message]
2003-09-24 18:29 ` David Mosberger
2003-09-24 18:31 ` Khalid Aziz
2003-09-24 18:58 ` Khalid Aziz
2003-09-24 19:25 ` David Mosberger

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