From: David Miller <davem@davemloft.net>
To: eric.dumazet@gmail.com
Cc: netdev@vger.kernel.org, ncardwell@google.com,
jeffrey.t.kirsher@intel.com, therbert@google.com,
herbert@gondor.hengli.com.au, bhutchings@solarflare.com,
mcarlson@broadcom.com, mchan@broadcom.com, maze@google.com,
ilpo.jarvinen@helsinki.fi
Subject: Re: [PATCH 4/4 net-next] tcp: makes tcp_try_coalesce aware of skb->head_frag
Date: Mon, 30 Apr 2012 21:48:47 -0400 (EDT) [thread overview]
Message-ID: <20120430.214847.426130586624369879.davem@davemloft.net> (raw)
In-Reply-To: <1335523113.2775.239.camel@edumazet-glaptop>
From: Eric Dumazet <eric.dumazet@gmail.com>
Date: Fri, 27 Apr 2012 12:38:33 +0200
> From: Eric Dumazet <edumazet@google.com>
>
> TCP coalesce can check if skb to be merged has its skb->head mapped to a
> page fragment, instead of a kmalloc() area.
>
> We had to disable coalescing in this case, for performance reasons.
>
> We 'upgrade' skb->head as a fragment in itself.
>
> This reduces number of cache misses when user makes its copies, since a
> less sk_buff are fetched.
>
> This makes receive and ofo queues shorter and thus reduce cache line
> misses in TCP stack.
>
> This is a followup of patch "net: allow skb->head to be a page fragment"
>
> Tested with tg3 nic, with GRO on or off. We can see "TCPRcvCoalesce"
> counter being incremented.
>
> Signed-off-by: Eric Dumazet <edumazet@google.com>
Applied.
prev parent reply other threads:[~2012-05-01 1:49 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-04-27 10:38 [PATCH 4/4 net-next] tcp: makes tcp_try_coalesce aware of skb->head_frag Eric Dumazet
2012-05-01 1:48 ` David Miller [this message]
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