Messages in this thread | | | Date | Thu, 29 Nov 2007 11:04:39 -0800 | From | "H. Peter Anvin" <> | Subject | Re: constant_tsc and TSC unstable |
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Paul Rolland (ポール・ロラン) wrote: > Hello, > > I've a machine with a Core2Duo CPU. /proc/cpuinfo reports the flag > constant_tsc, but at boot time, I have the log : > > ... > Total of 2 processors activated (6919.15 BogoMIPS). > ENABLING IO-APIC IRQs > ..TIMER: vector=0x31 apic1=0 pin1=2 apic2=-1 pin2=-1 > checking TSC synchronization [CPU#0 -> CPU#1]: > Measured 3978592228 cycles TSC warp between CPUs, turning off TSC clock. > Marking TSC unstable due to: check_tsc_sync_source failed. > Brought up 2 CPUs > ... > > This machine is running 2.6.23.1-21.fc7. I know I should report to Fedora, > but I was wondering if this is a bug or a feature ;) >
constant_tsc means the TSC doesn't change with CPU core frequency.
The problem you're having is that the TSCs of your two cores are completely different, over a second apart. This is a bug, unrelated to constant_tsc.
-hpa
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