Messages in this thread | | | From | Wolfgang Hoffmann <> | Subject | Re: [-rt] time-related problems with CPU frequency scaling | Date | Thu, 20 Apr 2006 20:39:30 +0200 |
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On Sunday 16 April 2006 20:41, Wolfgang Hoffmann wrote: > Now with speedstep enabled and CONFIG_HIGH_RES_TIMERS=y, I see some > anomalies: > - time-of-day lags gradually behind wallclock time
It turns out that this is a non-issue. I can't quite explain how I came to the impression that there is a clock lag, but current status is that the clock runs correctly. So sorry for the noise.
On Tuesday 18 April 2006 00:35, Lee Revell wrote: > On Sun, 2006-04-16 at 20:41 +0200, Wolfgang Hoffmann wrote: > > - if CPU frequency is low when jackd is started, it complains: > > "delay of 2915.000 usecs exceeds estimated spare > > time of 2847.000; restart ..." > > as soon as frequency is scaled up. Seems that jackd gets confused by > > some influence of CPU frequency on timekeeping? No problems as long as > > CPU frequency isn't scaled up, though. > > JACK still uses the TSC for timing and thus is incompatible with CPU > frequency scaling. You must use the -clockfix branch from CVS.
Thanks for the pointer, Lee. I'm now running the clockfix CVS branch and the problems are solved. So the -rt kernel is fine.
Thanks for the help, Wolfgang - 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/
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