From: David Miller <davem@davemloft.net>
To: pabeni@redhat.com
Cc: eric.dumazet@gmail.com, netdev@vger.kernel.org,
edumazet@google.com, jiri@mellanox.com, daniel@iogearbox.net,
ast@plumgrid.com, aduyck@mirantis.com, tom@herbertland.com,
peterz@infradead.org, mingo@kernel.org, riel@redhat.com,
hannes@stressinduktion.org, linux-kernel@vger.kernel.org
Subject: Re: [RFC PATCH 0/2] net: threadable napi poll loop
Date: Tue, 10 May 2016 16:45:38 -0400 (EDT) [thread overview]
Message-ID: <20160510.164538.1375529074383780155.davem@davemloft.net> (raw)
In-Reply-To: <1462911770.5333.11.camel@redhat.com>
From: Paolo Abeni <pabeni@redhat.com>
Date: Tue, 10 May 2016 22:22:50 +0200
> On Tue, 2016-05-10 at 09:08 -0700, Eric Dumazet wrote:
>> On Tue, 2016-05-10 at 18:03 +0200, Paolo Abeni wrote:
>>
>> > If a single core host is under network flood, i.e. ksoftirqd is
>> > scheduled and it eventually (after processing ~640 packets) will let the
>> > user space process run. The latter will execute a syscall to receive a
>> > packet, which will have to disable/enable bh at least once and that will
>> > cause the processing of another ~640 packets. To receive a single packet
>> > in user space, the kernel has to process more than one thousand packets.
>>
>> Looks you found the bug then. Have you tried to fix it ?
...
> The ksoftirq and the local_bh_enable() design are the root of the
> problem, they need to be touched/affected to solve it.
That's not what I read from your description, processing 640 packets
before going to ksoftirqd seems to the be the absolute root problem.
next prev parent reply other threads:[~2016-05-10 20:45 UTC|newest]
Thread overview: 48+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-05-10 14:11 [RFC PATCH 0/2] net: threadable napi poll loop Paolo Abeni
2016-05-10 14:11 ` [RFC PATCH 1/2] net: implement threaded-able napi poll loop support Paolo Abeni
2016-05-10 14:11 ` [RFC PATCH 2/2] net: add sysfs attribute to control napi threaded mode Paolo Abeni
2016-05-10 14:29 ` [RFC PATCH 0/2] net: threadable napi poll loop Eric Dumazet
2016-05-10 15:51 ` David Miller
2016-05-10 16:03 ` Paolo Abeni
2016-05-10 16:08 ` Eric Dumazet
2016-05-10 20:22 ` Paolo Abeni
2016-05-10 20:45 ` David Miller [this message]
2016-05-10 20:50 ` Rik van Riel
2016-05-10 20:52 ` David Miller
2016-05-10 21:01 ` Rik van Riel
2016-05-10 20:46 ` Hannes Frederic Sowa
2016-05-10 21:09 ` Eric Dumazet
2016-05-10 21:31 ` Eric Dumazet
2016-05-10 21:35 ` Rik van Riel
2016-05-10 21:53 ` Eric Dumazet
2016-05-10 22:02 ` Eric Dumazet
2016-05-10 22:44 ` Eric Dumazet
2016-05-10 22:02 ` Rik van Riel
2016-05-11 17:55 ` Eric Dumazet
2016-05-10 22:32 ` Hannes Frederic Sowa
2016-05-10 22:51 ` Eric Dumazet
2016-05-11 6:55 ` Peter Zijlstra
2016-05-11 13:13 ` Hannes Frederic Sowa
2016-05-11 14:40 ` Eric Dumazet
2016-05-11 15:01 ` Rik van Riel
2016-05-11 15:50 ` Eric Dumazet
2016-05-11 21:56 ` Eric Dumazet
2016-05-12 20:07 ` Paolo Abeni
2016-05-12 20:49 ` Eric Dumazet
2016-05-12 20:58 ` Paolo Abeni
2016-05-12 21:05 ` Eric Dumazet
2016-05-13 16:50 ` Paolo Abeni
2016-05-13 17:03 ` Eric Dumazet
2016-05-13 17:19 ` Paolo Abeni
2016-05-13 17:36 ` Eric Dumazet
2016-05-16 13:10 ` Paolo Abeni
2016-05-16 13:38 ` Eric Dumazet
2016-05-11 9:48 ` Paolo Abeni
2016-05-11 13:08 ` Eric Dumazet
2016-05-11 13:39 ` Hannes Frederic Sowa
2016-05-11 13:47 ` Hannes Frederic Sowa
2016-05-11 14:38 ` Paolo Abeni
2016-05-11 14:45 ` Eric Dumazet
2016-05-11 22:47 ` Hannes Frederic Sowa
2016-05-10 15:57 ` Thomas Gleixner
2016-05-10 20:41 ` Paolo Abeni
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