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From: Eric Dumazet <eric.dumazet@gmail.com>
To: Yevgeny Petrilin <yevgenyp@mellanox.co.il>
Cc: davem@davemloft.net, netdev@vger.kernel.org
Subject: Re: [PATCH 3/7] mlx4_en: Incoming traffic alignment optimizations
Date: Tue, 18 Oct 2011 03:53:19 +0200	[thread overview]
Message-ID: <1318902799.2571.26.camel@edumazet-laptop> (raw)
In-Reply-To: <4E9C8D53.5040006@mellanox.co.il>

Le lundi 17 octobre 2011 à 22:17 +0200, Yevgeny Petrilin a écrit :
> Packet headers are copied to skb linear part (which is IP aligned), so there is no reason for
> the scatter entry to be IP aligned.
> 
> Signed-off-by: Yevgeny Petrilin <yevgenyp@mellanox.co.il>
> ---

> @@ -91,7 +91,7 @@
>  /* Receive fragment sizes; we use at most 4 fragments (for 9600 byte MTU
>   * and 4K allocations) */
>  enum {
> -	FRAG_SZ0 = 512 - NET_IP_ALIGN,
> +	FRAG_SZ0 = 2048,
>  	FRAG_SZ1 = 1024,
>  	FRAG_SZ2 = 4096,
>  	FRAG_SZ3 = MLX4_EN_ALLOC_SIZE

Is the 512 -> 2048 change really wanted ? Its not mentioned in changelog
and is confusing.

This means mlx4 lost the ability to use a small frag (512 bytes) to
store small frames.

  reply	other threads:[~2011-10-18  1:53 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-10-17 20:17 [PATCH 3/7] mlx4_en: Incoming traffic alignment optimizations Yevgeny Petrilin
2011-10-18  1:53 ` Eric Dumazet [this message]
2011-10-18  7:43   ` Yevgeny Petrilin
2011-10-18  8:40     ` Eric Dumazet
2011-10-18  8:52       ` Yevgeny Petrilin

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