netdev - Re: [TCP] IPV6 : Change a divide into a right shift in tcp_v6_send

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Message-ID: <Pine.LNX.4.64.0712210919350.30982@kivilampi-30.cs.helsinki.fi>
Date:	Fri, 21 Dec 2007 09:21:06 +0200 (EET)
From:	"Ilpo Järvinen" <ilpo.jarvinen@...sinki.fi>
To:	Eric Dumazet <dada1@...mosbay.com>
cc:	"David S. Miller" <davem@...emloft.net>,
	"YOSHIFUJI Hideaki / 吉藤英明" 
	<yoshfuji@...ux-ipv6.org>,
	Linux Netdev List <netdev@...r.kernel.org>
Subject: Re: [TCP] IPV6 : Change a divide into a right shift in tcp_v6_send_ack()

On Fri, 21 Dec 2007, Eric Dumazet wrote:

> Because tot_len is signed in tcp_v6_send_ack(), tot_len/4 forces compiler
> to emit an integer divide, while we can help it to use a right shift,
> less expensive.

Can't you just change tot_len to unsigned here? It's just sizeof and some 
positive constants added...

-- 
 i.
View attachment "tcp_ipv6.patch" of type "text/plain" (415 bytes)