Dynamic Ticks/HZ
Joe Holden
lists at rewt.org.uk
Mon Nov 5 16:35:28 UTC 2012
Alexander Motin wrote:
> Hi.
>
> Full interrupt rate on some CPU means that your system is not idle, but
> running some process. Another possibility is that you have DUMMYNET
> compiled into your kernel, which tends to schedule callout for every HZ
> tick, effectively blocking skipping interrupts for one of CPUs.
>
> Check 'top -SH' for running processes, or 'top -SH -m io -o vcsw' for
> processes doing a lot of context switches. That most likely should give
> an answer.
>
Hi,
It looks like the device polling is what was causing it, once I'd
removed that from kernconf it returned to normal - full interupt rate is
ok though if I can increase the rate to a decent level
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