From: Eric Dumazet <eric.dumazet@gmail.com>
To: Kieran Mansley <kmansley@solarflare.com>
Cc: Ben Hutchings <bhutchings@solarflare.com>, netdev@vger.kernel.org
Subject: Re: TCPBacklogDrops during aggressive bursts of traffic
Date: Tue, 22 May 2012 22:54:36 +0200 [thread overview]
Message-ID: <1337720076.3361.667.camel@edumazet-glaptop> (raw)
In-Reply-To: <1337705135.3361.226.camel@edumazet-glaptop>
On Tue, 2012-05-22 at 18:45 +0200, Eric Dumazet wrote:
> This is not evident from the capture, you are mistaken.
>
> tcpdump captures packets before tcp stack, it doesnt say if they are :
>
> 1) queued in receive of ofo queue
> 2) queued in socket backlog
> 3) dropped because we hit socket rcvbuf limit
>
> If socket lock is hold by the user, packets are queued to backlog, or
> dropped.
>
> Then, when socket lock is about to be released, we process the backlog.
>
>
BTW, latest iproute2 ss util has nice information if you add -m :
misc/ss -m dst 192.168.99.2
State Recv-Q Send-Q Local Address:Port Peer Address:Port
ESTAB 3441896 0 192.168.99.1:44409 192.168.99.2:41197
skmem:(r5035136,rb6291456,t0,tb23080,f1149824,w0,o0)
Here you can see that for 3441896 bytes in TCP queue (payload),
we have 5035136 bytes in rmem_alloc,
and 6291456 'bytes' in sk_rcvbuf
It lacks the backlog len, I'll send a patch when net-next reopens.
next prev parent reply other threads:[~2012-05-22 20:54 UTC|newest]
Thread overview: 37+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-05-15 14:38 TCPBacklogDrops during aggressive bursts of traffic Kieran Mansley
2012-05-15 14:56 ` Eric Dumazet
2012-05-15 15:00 ` Eric Dumazet
2012-05-15 16:29 ` Kieran Mansley
2012-05-15 16:34 ` Eric Dumazet
2012-05-15 16:47 ` Ben Hutchings
2012-05-15 17:01 ` Eric Dumazet
2012-05-15 17:23 ` Eric Dumazet
2012-05-17 16:31 ` Kieran Mansley
2012-05-17 16:37 ` Eric Dumazet
2012-05-18 15:45 ` Kieran Mansley
2012-05-18 15:49 ` Eric Dumazet
2012-05-18 15:53 ` Kieran Mansley
2012-05-18 18:40 ` Eric Dumazet
2012-05-22 8:20 ` Kieran Mansley
2012-05-22 9:25 ` Eric Dumazet
2012-05-22 9:30 ` Eric Dumazet
2012-05-22 15:09 ` Kieran Mansley
2012-05-22 16:12 ` Eric Dumazet
2012-05-22 16:32 ` Kieran Mansley
2012-05-22 16:45 ` Eric Dumazet
2012-05-22 20:54 ` Eric Dumazet [this message]
2012-05-23 9:44 ` Eric Dumazet
2012-05-23 12:09 ` Eric Dumazet
2012-05-23 16:04 ` Alexander Duyck
2012-05-23 16:12 ` Eric Dumazet
2012-05-23 16:39 ` Eric Dumazet
2012-05-23 17:10 ` Alexander Duyck
2012-05-23 21:19 ` Alexander Duyck
2012-05-23 21:37 ` Eric Dumazet
2012-05-23 22:03 ` Alexander Duyck
2012-05-23 16:58 ` Alexander Duyck
2012-05-23 17:24 ` Eric Dumazet
2012-05-23 17:57 ` Alexander Duyck
2012-05-23 17:34 ` David Miller
2012-05-23 17:46 ` Eric Dumazet
2012-05-23 17:57 ` David Miller
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