On Sat, 14 Apr 2001, Karim Yaghmour wrote:

Gabriel Paubert wrote:

quoted

Given that time handling is completely different in 2.2 and 2.4, it is
surprising. This would indicate that a decrementer interrupt has happened
too early.

How often does it happen ? Does it still happen with recent kernels ?
Were you running something that touches the decrementer (MOL, RTLINUX) ?

I can't tell you if the interrupt is happening too early or not,
although code could be added to check this.

Yes, currently the decrementer interrupt assumes that it is the only user.
This is quite simple however, use a while() {} instead of a do {}
while() in the loop that catches up on pending decrementer interrupts.

I can tell you that this has been noticed by more than one person.
I noticed this and so did the person at MontaVista that contributed
the cross-platform reading code (to enable traces to be read accross
different endian machines).

If you really want to see what I mean I could forward you a textual
trace sample to proove my point.

This could be very helpful (but from a recent kernel, please).

The latest kernel I've tested this on is 2.4.0-test10.

Ok, the new code was introduced with test9. I'm very surprised since I've
heavily tested it (time stamping lots of interrupts+NTP), but I'm going to
add more thorough checks to see if I can catch some problem. I'll come
back after a few billion do_gettimeofday() calls.

	Regards,
	Gabriel.


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