Re: [PATCH v2 net-next] softirq: reduce latencies

From: David Miller
Date: Fri Jan 04 2013 - 16:48:59 EST

From: Eric Dumazet <eric.dumazet@xxxxxxxxx>
Date: Thu, 03 Jan 2013 23:49:40 -0800

> From: Eric Dumazet <edumazet@xxxxxxxxxx>
> In various network workloads, __do_softirq() latencies can be up
> to 20 ms if HZ=1000, and 200 ms if HZ=100.
> This is because we iterate 10 times in the softirq dispatcher,
> and some actions can consume a lot of cycles.
> This patch changes the fallback to ksoftirqd condition to :
> - A time limit of 2 ms.
> - need_resched() being set on current task
> When one of this condition is met, we wakeup ksoftirqd for further
> softirq processing if we still have pending softirqs.
> Signed-off-by: Eric Dumazet <edumazet@xxxxxxxxxx>

Acked-by: David S. Miller <davem@xxxxxxxxxxxxx>
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