Re: [1/3] Bugfix: Don't use the TSC in sched_clock if unstable

From: Guillaume Chazarain
Date: Sun Mar 04 2007 - 13:33:25 EST


2007/3/4, Andi Kleen <ak@xxxxxxx>:

On what hardware?

Pentium M 798 MHz -> 2GHz

And how many frequency transitions do you have per second?

10 in a kernel compile exhibiting audio skips.

Anyway, the "Clocksource tsc unstable (delta = -263211549 ns)" line
in the dmesg I attached to the previous mail confirms IMHO that my
TSC is too unstable for scheduling purpose.

15 minutes after booting, including a kernel compile halted on the
first audio skip, I have this in
/sys/devices/system/cpu/cpu0/cpufreq/stats/trans_table

From : To
: 1995000 1596000 1330000 1064000 798000
1995000: 0 67 101 128 367
1596000: 20 0 3 3 41
1330000: 21 0 0 10 73
1064000: 30 0 0 0 111
798000: 592 0 0 0 0

Nothing alarming I presume.

Thanks.

--
Guillaume

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