From: David Miller <davem@davemloft.net>
To: xiaosuo@gmail.com
Cc: kuznet@ms2.inr.ac.ru, pekkas@netcore.fi, jmorris@namei.org,
yoshfuji@linux-ipv6.org, kaber@trash.net, netdev@vger.kernel.org
Subject: Re: [PATCH] net: remove tests on 64bit platforms
Date: Mon, 24 Jan 2011 23:30:57 -0800 (PST) [thread overview]
Message-ID: <20110124.233057.115949202.davem@davemloft.net> (raw)
In-Reply-To: <1295929298-13163-1-git-send-email-xiaosuo@gmail.com>
From: Changli Gao <xiaosuo@gmail.com>
Date: Tue, 25 Jan 2011 12:21:38 +0800
> On 64bit platforms, >31 bit shifting of a unsigned long variable is
> valid, so we can remove the related boundary tests, which may slow
> down the CPU if branch prediction fails.
The key word is "may", you don't actually know if this kind of
change actually matters for performance in practice.
I'm not applying this.
prev parent reply other threads:[~2011-01-25 7:30 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-01-25 4:21 [PATCH] net: remove tests on 64bit platforms Changli Gao
2011-01-25 4:28 ` Ben Hutchings
2011-01-25 7:30 ` David Miller [this message]
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