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

From: David Mosberger <davidm_at_napali.hpl.hp.com>
Date: 2003-09-25 04:02:21
>>>>> On Wed, 24 Sep 2003 11:21:19 -0600 (MDT), Khalid Aziz <khalid@fc.hp.com> said:

  Khalid> do_gettimeofday() needs to account for lost ticks before
  Khalid> returning current time and it fails to do
  Khalid> that. do_gettimeofday() on other architectures compensate
  Khalid> for lost ticks correctly. Due to this bug, if you repeatedly
  Khalid> do clock_settime() immediately followed by clock_gettime()
  Khalid> and compare the time returned by clock_gettime() to the time
  Khalid> set by clock_settime(), you will eventually see clock going
  Khalid> backwards. I am attaching a test program from POSIX
  Khalid> testsuite at the end that exposes this bug. Run this test in
  Khalid> a continuous loop that stops when test fails.

This explanation doesn't sound right.  See the "lost" variable in
gettimeoffset().  It's supposed to account for lost ticks.

	--david

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Received on Wed Sep 24 14:05:43 2003

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