Messages in this thread | | | Date | Tue, 24 Jan 2006 09:13:01 +0100 | From | Ingo Molnar <> | Subject | Re: RCU latency regression in 2.6.16-rc1 |
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* Lee Revell <rlrevell@joe-job.com> wrote:
> On Tue, 2006-01-24 at 09:01 +0100, Ingo Molnar wrote: > > * Lee Revell <rlrevell@joe-job.com> wrote: > > > > > On Tue, 2006-01-24 at 08:56 +0100, Ingo Molnar wrote: > > > > * Lee Revell <rlrevell@joe-job.com> wrote: > > > > > > > > > I ported the latency tracer to 2.6.16 and got this 13ms latency within > > > > > a few hours. This is a regression from 2.6.15. > > > > > > > > > > It appears that RCU can invoke ipv4_dst_destroy thousands of times in > > > > > a single batch. > > > > > > > > could you try the PREEMPT_RCU patch below? > > > > > > Sure. If it works do you see this making it in 2.6.16? Otherwise we > > > still would have a regression... > > > > nope, that likely wont make v2.6.16, which is frozen already. > > > > How about just lowering maxbatch to 1000?
does that fix the latency for you? I think "maxbatch=1000" should work as a boot parameter too.
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