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

David Mosberger
2003-09-24T18:02:21Z

>>>>> 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