lkml.org 
[lkml]   [2004]   [Jan]   [20]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Subject2.6.1 "clock preempt"?
From
Date
hello,

i've started to test the 2.6 series of kernels and observed a
strange thing: with moderate background load, the system clock
(i.e. time) seems to slow down to about 60% of normal speed
and the normally reliable ntp process (v4.2.0)

details: working interactively with a couple of background dummy
processes (*1), my system clock slowed down approx 90 mins over
a period of approx 4 hrs real time.

(*1) infinite loop: 1 rip, 1 encode -- both run at nice 10

the kernel logs show messages on the form:

localhost kernel: Losing too many ticks!
localhost kernel: TSC cannot be used as a timesource.
(Are you running with SpeedStep?)
localhost kernel: Falling back to a sane timesource.
localhost kernel: set_rtc_mmss: can't update from 5 to 58

without the background load, the system keeps perfect time.

==> any ideas of what could be going on would be appreciated.

hardware details
Intel P4 2.53gz on Supermicro P4SAA mobo (Intel 7205 chipset)
1gb memory; multiple drives; Promise Ultra/133 raid controller
software
kernel 2.6.1 w/APIC and PREEMPT options turned on.
Fedora Core 1 + selected development packages (verified on 2.4).

more info available on request.

regards,
--
Steinar Hauan, dept of ChemE -- hauan@cmu.edu
Carnegie Mellon University, Pittsburgh PA, USA


-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/

\
 
 \ /
  Last update: 2005-03-22 14:00    [from the cache]
©2003-2014 Jasper Spaans. hosted at Digital Ocean