Messages in this thread | | | Subject | Re: Hang and Soft Lockup problems with generic time code | From | James Bottomley <> | Date | Fri, 07 Jul 2006 23:36:44 -0500 |
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On Fri, 2006-07-07 at 16:39 -0700, john stultz wrote: > Yep. This has been seen where a large number of ticks are lost. Roman > and I are working on a solution for this (I sent a patch out to the > list > earlier today for it, and Roman *just* posted his version a moment ago > - > if you can give one or both of them a try it would be appreciated).
Well, the patch you posted here:
Message-ID: 1152298515.5330.12.camel () localhost ! localdomain
Seems to work fine, thanks. I'm not sure what I'm looking for for the other one.
> Did you really mean jumps of 200 seconds? Hmmm. The issue Roman and I > have been looking into does occur when we lose a number of ticks and > that confuses the clocksource adjustment code. The fix we're working > on > corrects the adjustment confusion, but doesn't fix the lost ticks. > > However 200 seconds of lost ticks sounds very off. Could the driver be > disabling interrupt for such a long period of time?
Well, what I was seeing was that
clocksource_read(clock) - clock->cycle_last
is returning a value about 200 x clock->cycle_interval
According to the debugging printks I put into update_wall_time(). I was assuming this was caused by a jump in the TSC count, but I suppose it could also be cause by spurious alterations to cycle_last or other effects I haven't traced.
James
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