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From: Eric Dumazet <eric.dumazet@gmail.com>
To: "Maciej Żenczykowski" <maze@google.com>
Cc: David Miller <davem@davemloft.net>,
	ilpo.jarvinen@helsinki.fi, rick.jones2@hp.com,
	netdev@vger.kernel.org, therbert@google.com,
	ncardwell@google.com, ycheng@google.com
Subject: Re: [RFC] allow skb->head to point/alias to first skb frag
Date: Thu, 26 Apr 2012 14:32:34 +0200	[thread overview]
Message-ID: <1335443554.2775.33.camel@edumazet-glaptop> (raw)
In-Reply-To: <CANP3RGdnZk5b-gMkF8BPScrp9xos4X1u3n58ocuBQhTT7taE8A@mail.gmail.com>

On Thu, 2012-04-26 at 03:09 -0700, Maciej Żenczykowski wrote:
> it would be very useful if there was an api for freeing skb->head memory...
> 
> I've fooled around with a single memory buffer for both the head and
> the data and seen huge performance wins under heavy packet load (half
> the amount of malloc/free), but could never quite get it to be 100%
> stable.

My patch is almost ready, and seems very good.

I added a param to skb_build() to tell the memory comes from a (sub)page

tg3 uses the new thing.

GRO does the correct merging.

(by the way, I noticed GRO lies about skb truesize... since it
accumulates frag lengths instead of allocated space... with a 1448/2048
mismatch for MTU=1500)

And this apparently solves my slub performance issue I had on my dual
quad core machine, since I no longer hit slub slow path.

  reply	other threads:[~2012-04-26 12:32 UTC|newest]

Thread overview: 37+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-04-23  9:38 [PATCH 2/2 net-next] tcp: sk_add_backlog() is too agressive for TCP Eric Dumazet
2012-04-23 17:14 ` Rick Jones
2012-04-23 17:23   ` Eric Dumazet
2012-04-23 20:01     ` David Miller
2012-04-23 20:37       ` Eric Dumazet
2012-04-23 20:57         ` Rick Jones
2012-04-23 21:30           ` Eric Dumazet
2012-04-23 21:51             ` Rick Jones
2012-04-23 21:56               ` Rick Jones
2012-04-23 22:05               ` Eric Dumazet
2012-04-23 22:16                 ` Rick Jones
2012-04-24 15:25                   ` Christoph Lameter
2012-04-23 21:01         ` David Miller
2012-04-23 21:38           ` Eric Dumazet
2012-04-24  2:20         ` Eric Dumazet
2012-04-24  2:27           ` David Miller
2012-04-24  8:01           ` Ilpo Järvinen
2012-04-24  8:10             ` David Miller
2012-04-24  8:21               ` Ilpo Järvinen
2012-04-24  8:25                 ` David Miller
2012-04-24  8:40                   ` Ilpo Järvinen
2012-04-24  8:48                     ` David Miller
2012-04-24 10:32                       ` Ilpo Järvinen
2012-04-24  8:56                     ` Eric Dumazet
2012-04-26  8:10                       ` [RFC] allow skb->head to point/alias to first skb frag Eric Dumazet
2012-04-26  8:36                         ` David Miller
2012-04-26  9:10                           ` Eric Dumazet
2012-04-26  9:18                             ` David Miller
2012-04-26  9:22                               ` Eric Dumazet
2012-04-26 10:09                                 ` Maciej Żenczykowski
2012-04-26 12:32                                   ` Eric Dumazet [this message]
2012-04-26 13:50                                     ` Eric Dumazet
2012-04-26 20:12                                       ` David Miller
2012-04-26 20:18                                         ` Eric Dumazet
2012-04-24  8:49             ` [PATCH 2/2 net-next] tcp: sk_add_backlog() is too agressive for TCP Eric Dumazet
2012-04-24  8:44         ` David Laight
2012-04-24  8:53           ` Eric Dumazet

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