From: Eric Dumazet <eric.dumazet@gmail.com>
To: Jesper Dangaard Brouer <brouer@redhat.com>
Cc: David Miller <davem@davemloft.net>,
hans.schillstrom@ericsson.com, subramanian.vijay@gmail.com,
dave.taht@gmail.com, netdev@vger.kernel.org,
ncardwell@google.com, therbert@google.com, mph@hoth.dk
Subject: Re: [PATCH v2 net-next] tcp: avoid tx starvation by SYNACK packets
Date: Wed, 27 Jun 2012 09:30:16 +0200 [thread overview]
Message-ID: <1340782216.10893.427.camel@edumazet-glaptop> (raw)
In-Reply-To: <1340781845.2028.133.camel@localhost>
On Wed, 2012-06-27 at 09:24 +0200, Jesper Dangaard Brouer wrote:
> But, I still believe that we need, to solve this SYN issues by parallel
> processing of packets. (It seems Eric and Hans are looking at a single
> core SYN processing scheme, but I might have missed their point).
Yep
Parallel processing will only benefit multiqueue setups.
Many linux servers in colocations are still using a mono queue NIC, and
default linux configuration is to use a single cpu to handle all
incoming frames (no RPS/RFS).
Sometime the hw IRQ itself is distributed among several cpus, but at one
single moment, only one cpu is serving the NAPI poll.
As long as the LISTEN processing is locking the socket, there is no
point distributing SYN packets to multiple cpus, this only adds
contention and poor performance because of false sharing.
My plan is to get rid of the socket lock for LISTEN and use RCU instead.
next prev parent reply other threads:[~2012-06-27 7:30 UTC|newest]
Thread overview: 42+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-05-31 21:56 [PATCH net-next] tcp: avoid tx starvation by SYNACK packets Eric Dumazet
2012-05-31 23:03 ` David Miller
2012-06-01 4:48 ` Eric Dumazet
2012-06-01 17:46 ` David Miller
2012-06-01 7:00 ` [PATCH] tcp: do not create inetpeer on SYNACK message Eric Dumazet
2012-06-01 18:24 ` David Miller
2012-06-01 21:34 ` Hans Schillström
2012-06-02 6:56 ` Eric Dumazet
2012-06-01 7:36 ` [PATCH net-next] tcp: avoid tx starvation by SYNACK packets Hans Schillstrom
2012-06-01 9:34 ` Eric Dumazet
2012-06-02 1:28 ` Dave Taht
2012-06-02 5:46 ` Eric Dumazet
2012-06-23 7:34 ` Vijay Subramanian
2012-06-23 8:42 ` [PATCH v2 " Eric Dumazet
2012-06-25 6:24 ` Hans Schillstrom
2012-06-25 22:43 ` David Miller
2012-06-26 4:51 ` Eric Dumazet
2012-06-26 4:55 ` David Miller
2012-06-26 5:34 ` Hans Schillstrom
2012-06-26 7:11 ` David Miller
2012-06-26 7:27 ` Hans Schillstrom
2012-06-26 17:02 ` Eric Dumazet
2012-06-27 5:23 ` Hans Schillstrom
2012-06-27 8:22 ` David Miller
2012-06-27 8:25 ` Jesper Dangaard Brouer
2012-06-27 8:30 ` Hans Schillstrom
2012-06-27 8:40 ` Eric Dumazet
2012-06-27 8:48 ` David Miller
2012-06-27 6:32 ` Jesper Dangaard Brouer
2012-06-27 6:54 ` David Miller
2012-06-27 7:24 ` Jesper Dangaard Brouer
2012-06-27 7:30 ` Eric Dumazet [this message]
2012-06-27 7:54 ` Jesper Dangaard Brouer
2012-06-27 8:02 ` Eric Dumazet
2012-06-27 8:21 ` Jesper Dangaard Brouer
2012-06-27 8:45 ` Eric Dumazet
2012-06-27 9:23 ` Jesper Dangaard Brouer
2012-06-27 8:13 ` David Miller
2012-06-27 19:50 ` Florian Westphal
2012-06-27 21:39 ` Eric Dumazet
2012-06-27 22:23 ` David Miller
2012-06-27 22:23 ` David Miller
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