time issues

Matthew Dillon dillon at apollo.backplane.com
Thu Oct 28 00:55:25 PDT 2004


:I've seen something similar to this with HEAD just before the last big
:slip of DragonFly_Stable to HEAD, but I haven't manageged to reproduce it
:since then. I can't say whether the system clock was completely dead, or that
:it just slowed down.
:
:By the way, is TIMER_USE_1 safe for anyone? Only tested with SMP, but:
:
:- I've only seen the slow down of system clock on kernel *without* TIMER_USE_1,
:  but now I can't reproduce it. The system clock never goes fast *without*
:  TIMER_USE_1.
:
:- on kernel *with* TIMER_USE_1 on the same machine, the system clock
:  goes crazy(about 10 times faster than the real time) a few minutes after
:  staring buildworld. If I reboot without running ntpdate, the clock goes
:  back to normal(I mean the hard clock doesn't seem to be affected).
:  The machine has 4 logical CPUs(dual Xeon with HTT enabled). If I turn off
:  HTT in the BIOS, the number of logical CPU becomes 2, and this time
:  the system clock will not be as fast as it did with HTT enabled
:  (like 5 times or so faster than the real time).

    When I try to use TIMER_USE_1 something goes nuts in the system while
    it is booting.  It's really weird, I've never been able to figure it out.

    I think there are definitely some issues with the timekeeping but I
    think I am going to wait until after VFS and journaling go in before
    I make a push to track it down.

					-Matt
					Matthew Dillon 
					<dillon at xxxxxxxxxxxxx>





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