From: Anton Blanchard <anton@samba.org>
To: "Jörn Engel" <joern@wohnheim.fh-wedel.de>
Cc: Thomas Klein <tklein@de.ibm.com>, netdev <netdev@vger.kernel.org>,
linux-kernel <linux-kernel@vger.kernel.org>,
linux-ppc <linuxppc-dev@ozlabs.org>,
Christoph Raisch <raisch@de.ibm.com>,
Marcus Eder <meder@de.ibm.com>
Subject: Re: [PATCH 1/6] ehea: interface to network stack
Date: Tue, 15 Aug 2006 00:38:42 +1000 [thread overview]
Message-ID: <20060814143842.GM479@krispykreme> (raw)
In-Reply-To: <20060814112656.GC10164@wohnheim.fh-wedel.de>
> Is a conditional cheaper than a divide? In case of a misprediction I
> would assume it to be significantly slower and I don't know the ratio
> of mispredictions for this branch.
A quick scan of the web shows 40 cycles for athlon64 idiv, and its
similarly slow on many other cpus. Even assuming you mispredict every
branch its going to be a win.
Anton
next prev parent reply other threads:[~2006-08-14 14:38 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2006-08-09 8:38 [PATCH 1/6] ehea: interface to network stack Jan-Bernd Themann
2006-08-09 9:08 ` Christian Borntraeger
2006-08-11 11:02 ` Jan-Bernd Themann
2006-08-09 13:06 ` Alexey Dobriyan
2006-08-10 14:49 ` Jan-Bernd Themann
2006-08-10 6:15 ` Michael Ellerman
2006-08-10 7:30 ` Michael Ellerman
2006-08-10 14:28 ` Jan-Bernd Themann
2006-08-11 20:56 ` Anton Blanchard
2006-08-14 11:26 ` Jörn Engel
2006-08-14 14:38 ` Anton Blanchard [this message]
2006-08-14 15:43 ` Jan-Bernd Themann
2006-08-14 16:59 ` Arnd Bergmann
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