Messages in this thread | | | From | Jonathan Woithe <> | Subject | Re: 2.6.14-rt21: slow-running clock | Date | Thu, 15 Dec 2005 13:48:36 +1030 (CST) |
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Hi John
> > > On Fri, 2005-12-09 at 12:49 +1030, Jonathan Woithe wrote: > > > > > I'm now working on why we mis-compensate the c3tsc clocksource in the > > > > > -RT tree. > > > > > > > > No problem. Let me know when you have something to test or need further > > > > info. > > > > > > Attached is a test patch to see if it doesn't resolve the issue for > > > you. I get a maximum change in drift of 30ppm when idling between C3 > > > states by being more careful with the C3 TSC compensation and I also > > > force timekeeping updates when cpufreq events occur. > > > > Unfortunately there's still an issue. > > Ah, drat. > > I'm just going to dump the c3tsc clocksource for now. If C3 mode is > available, the ACPI PM timer is available (since it is used for C3 > timing), so we'll just fall back to ACPI PM if we see the cpu entering > C3 mode. > > I'm working to respin a new release tonight, hopefully that will make it > upstream to -rt soon and that should take care of it. Later I can look > at reworking the c3tsc clocksource, but for now things need to just > work.
Not a problem - I'll test this next release soon (perhaps via -rt) and confirm that things "just work" for me. I'm happy to keep testing things - if you do need further tests done for c3tsc in future drop me a line.
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