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

From: David Mosberger <>
Date: 2003-09-25 04:29:18
>>>>> On Wed, 24 Sep 2003 12:17:41 -0600, Khalid Aziz <> said:

  Khalid> So it would seem. What would then explain clock going
  Khalid> backwards? Here is what I see when the test fails:

  Khalid> tpget=1037128357,995121000, tpset=1037128358,0

  Khalid> where tpget is what was returned by gettimeofday() and tpset
  Khalid> is what was set by settimeofday(). Clock seems to have moved
  Khalid> back by 4.879 msec.

Not sure off-hand and I haven't looked at the 2.4 code-base in a
while, but aren't we double-compensating in do_settimeofday()?  There,
we have:

		tv->tv_usec -= gettimeoffset();
		tv->tv_usec -= (jiffies - wall_jiffies) * (1000000 / HZ);

Perhaps the second line just needs to go?

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Received on Wed Sep 24 14:29:39 2003

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