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

David Miller
2013-01-04T21:49:11Z

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

> From: Eric Dumazet <edumazet@google.com>
>
> 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@google.com>

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