From: "David S. Miller" <davem@davemloft.net>
To: ak@suse.de
Cc: rml@novell.com, akpm@osdl.org, linux-kernel@vger.kernel.org
Subject: Re: [patch] IBM HDAPS accelerometer driver, with probing.
Date: Fri, 26 Aug 2005 19:49:05 -0700 (PDT) [thread overview]
Message-ID: <20050826.194905.11108278.davem@davemloft.net> (raw)
In-Reply-To: <p73vf1skt0g.fsf@verdi.suse.de>
From: Andi Kleen <ak@suse.de>
Date: 27 Aug 2005 04:34:07 +0200
> "David S. Miller" <davem@davemloft.net> writes:
>
> > From: Alexey Dobriyan <adobriyan@gmail.com>
> > Date: Sat, 27 Aug 2005 02:58:48 +0400
> >
> > > What's the point of having unlikely() attached to every possible if ()?
> >
> > If can result in smaller code, for one thing, even if it
> > isn't a performance critical path.
>
> Really? At least on x86 it tends to generate bigger code when
> block reordering is enabled because a jump forward and a jump
> backward and a possible label alignment are bigger than just
> a single jump forward.
In the cases I've studied on sparc64 it keeps gcc from doing basic
block replication in the unlikely paths.
I've only checked gcc-3.4 and earlier, gcc-4.x is just big bloated
useless garbage and should be avoided for a couple of years.
next prev parent reply other threads:[~2005-08-27 2:49 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2005-08-26 22:18 Robert Love
2005-08-26 22:44 ` Dmitry Torokhov
2005-08-26 23:37 ` Robert Love
2005-08-27 5:29 ` Arnaldo Carvalho de Melo
2005-08-27 14:45 ` Alan Cox
2005-08-26 22:58 ` Alexey Dobriyan
2005-08-26 23:15 ` David S. Miller
2005-08-27 2:34 ` Andi Kleen
2005-08-27 2:49 ` David S. Miller [this message]
2005-08-27 4:06 ` Mitchell Blank Jr
2005-08-27 5:34 ` Arnaldo Carvalho de Melo
2005-08-27 6:12 ` Dmitry Torokhov
2005-08-27 11:35 ` Alexey Dobriyan
2005-08-27 14:56 ` Andi Kleen
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