netdev - Re: [PATCH net-next] net: batch calls to flush_all

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Date:   Fri, 26 Aug 2016 22:21:04 +0200
From:   Hannes Frederic Sowa <hannes@...essinduktion.org>
To:     Eric Dumazet <eric.dumazet@...il.com>,
        David Miller <davem@...emloft.net>
Cc:     netdev <netdev@...r.kernel.org>, Paolo Abeni <pabeni@...hat.com>
Subject: Re: [PATCH net-next] net: batch calls to flush_all_backlogs()

On Fri, Aug 26, 2016, at 21:50, Eric Dumazet wrote:
> From: Eric Dumazet <edumazet@...gle.com>
> 
> After commit 145dd5f9c88f ("net: flush the softnet backlog in process
> context"), we can easily batch calls to flush_all_backlogs() for all
> devices processed in rollback_registered_many()
> 
> Tested:
> 
> Before patch, on an idle host.
> 
> modprobe dummy numdummies=10000
> perf stat -e context-switches -a rmmod dummy
> 
>  Performance counter stats for 'system wide':
> 
>          1,211,798      context-switches
> 
>        1.302137465 seconds time elapsed
> 
> After patch:
> 
> perf stat -e context-switches -a rmmod dummy
> 
>  Performance counter stats for 'system wide':
> 
>            225,523      context-switches
> 
>        0.721623566 seconds time elapsed

Cool demonstration! :}

Acked-by: Hannes Frederic Sowa <hannes@...essinduktion.org>