Re: RCU latency regression in 2.6.16-rc1

[Ingo Molnar]

* Paul E. McKenney <paulmck@xxxxxxxxxx> wrote:

> > Have not tested yet but it appears that will reduce it substantially:
> > 
> > $ grep "dst_destroy (dst_rcu_free)" /proc/latency_trace | wc -l
> > 3027
> > 
> > This implies the latency would be reduced to ~4ms, still not great but
> > it will be overshadowed by rt_run_flush/rt_garbage_collect.
> 
> The other patch to try would be Dipankar Sarma's patch at:
> 
> 	http://marc.theaimsgroup.com/?l=linux-kernel&m=113657112726596&w=2
> 
> This patch was primarily designed to reduce memory overhead, but given 
> that it tends to reduce batch size, it should also reduce latency.

if this solves Lee's problem, i think we should apply this as a fix, and 
get it into v2.6.16. The patch looks straightforward and correct to me.

	Ingo
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