Messages in this thread | | | Subject | Re: 2.5.69 Interrupt Latency | From | Paul Fulghum <> | Date | 08 May 2003 14:35:18 -0500 |
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On Thu, 2003-05-08 at 14:22, Andrew Morton wrote: > Paul Fulghum <paulkf@microgate.com> wrote: > > > > On Wed, 2003-05-07 at 17:28, Andrew Morton wrote: > > > Paul Fulghum <paulkf@microgate.com> wrote: > > > > > > > > 2.5.69 > > > > Latency 100-110usec (5x increase) > > > > Spikes from 5-10 milliseconds > > > >
> > I'm going to try your suggestion of doing a stack dump > > when the driver encounters the large spikes in IRQ latency, > > to determine if something is leaving interrupts disabled. > > I wasn't very informative, alas.
Yeah, I've been reading through the 2.5.69 patch again and could not really see anything that related to the stack dump.
> > That will not address the fact that the minimum > > latency has jumped from 20usec (2.4.20 - 2.5.68) to 100usec > > (2.5.69). This may actually be two separate problems > > introduced with 2.5.69 > > Can you pinpoint a kernel version at which it started to happen?
Exactly with 2.5.69
2.5.68 works fine as do earlier versions back to 2.4.20-8 (earliest tested for this problem). All these versions have very consistant latencies as described above.
The problem definately started with the 2.5.69
-- Paul Fulghum, paulkf@microgate.com Microgate Corporation, http://www.microgate.com
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