Messages in this thread | | | Subject | Re: preempt-rt, NUMA and strange latency traces | From | Lee Revell <> | Date | Thu, 09 Feb 2006 15:02:44 -0500 |
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On Thu, 2006-02-09 at 12:24 +0100, Sébastien Dugué wrote: > On Thu, 2006-02-09 at 01:04 -0500, Lee Revell wrote: > > On Wed, 2006-02-08 at 11:45 +0100, Sébastien Dugué wrote: > > > The more I think about it, the more I tend to believe it's hardware > > > related. It seems as if the CPU just hangs for ~27 ms before > > > resuming processing. > > > > That would be an exceptionally long latency - you would probably notice > > it if the mouse froze, VOIP dropped out, ping stops, etc for 30ms. > > > > It's a test machine and I use it remotely with console redirected so > no mouse, no RT applications aside from my silly nanosleep() loop. But > I do notice that that test sometimes takes more time (ie when I get > those weird latencies).
Argh. You would think the vendors would consider a 30ms delay unacceptable. This is big enough to show up on an MRTG graph of ping times ferchrissake.
I guess the assumption is that most hardware will never be used for even soft RT work...
Lee
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