Messages in this thread | | | Date | Mon, 17 Aug 2009 20:34:02 +0200 (CEST) | From | Thomas Gleixner <> | Subject | Re: clocksource changes in 2.6.31 - possible regression |
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On Mon, 17 Aug 2009, Stephen Hemminger wrote: > On Mon, 17 Aug 2009 11:15:54 -0700 > john stultz <johnstul@us.ibm.com> wrote: > > > > The behavior you describe where you can't switch to the TSC, may be due > > > > to the TSC disqualification code marking it as non HRT compatible > > > > (again, I need to double check). While I'm not sure that's really > > > > correct, as the TSC is fine for HRT, in this case on your box, the TSC > > > > has been marked as unstable (likely due to being unsynced on old AMD SMP > > > > systems). There is a real chance that the timekeeping code on your > > > > system could see the TSC go backwards, calculate a negative time > > > > interval, and then end up hanging. > > > > > > > > > > TSC was alway stable on this box, and worked fine. There was no > > > message in log about TSC instability. The change was bisected > > > down to that one commit. > > > > But just to clarify, the TSC was never selected as the default > > clocksource on the box either, right? > > correct. > > I am okay with turning it off on boot command line for my tests, > but it might be an issue for other users.
Can you please provide a full dmesg of pre 31 and the output of /sys/.../available_clocksources before you switch to TSC ?
Thanks,
tglx
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