Re: [PATCH] do_gettimeofday() fails to compensate for lost ticks

From: Jesse Barnes <jbarnes_at_sgi.com>
Date: 2003-09-25 04:21:51
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=1037128357,995121000, tpset=1037128358,0
> 
> 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
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Received on Wed Sep 24 14:22:35 2003

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