Messages in this thread | | | Subject | Re: Hang and Soft Lockup problems with generic time code | From | john stultz <> | Date | Sat, 08 Jul 2006 14:47:02 -0700 |
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On Fri, 2006-07-07 at 23:36 -0500, James Bottomley wrote: > > 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
That then would be ~200 ticks. Is this at HZ=1000 ?
> 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.
Since this issue effected both the TSC and ACPI PM timer, I'd more likely suspect something is holding off the timer interrupt. This could be some kernel code like a driver, or it could be something like an SMI from the BIOS.
thanks -john
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