Re: [patch] voluntary-preempt-2.6.8.1-P4

Lee Revell
2004-08-20T09:15:03Z

On Fri, 2004-08-20 at 04:13, Ingo Molnar wrote:
> * Lee Revell <rlrevell@joe-job.com> wrote:
>
> > > http://redhat.com/~mingo/voluntary-preempt/voluntary-preempt-2.6.8.1-P4
> >
> > I think I am seeing those weird ~1 ms latencies still (actually I am not
> > sure I saw before now):
> >
> > http://krustophenia.net/testresults.php?dataset=2.6.8.1-P4#/var/www/2.6.8.1-P4/kswapd_latency_trace.txt
>
> this is a 9 msec latency in fact. I know what's going on - it's the
> get_swap_page() locking - i looked at it once already but there's no
> immediate silver arrow. As we allocate more and more swap entries the
> longer the scan gets.
>

This is an extreme load situation, so I don't think it will be a
real-world problem. I have not seen it under any normal workload.

What about this one:

http://krustophenia.net/testresults.php?dataset=2.6.8.1-P4#/var/www/2.6.8.1-P4/netif_receive_skb_latency_trace.txt

This appears during normal use.

Lee