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Date:      Tue, 11 Nov 2003 04:33:29 -0000
From:      des@des.no (Dag-Erling =?iso-8859-1?q?Sm=F8rgrav?=)
To:        Peter Wemm <peter@wemm.org>
Cc:        cvs-src@FreeBSD.org
Subject:   Re: cvs commit: src/sys/i386/i386 pmap.c
Message-ID:  <20031111041442.31922.qmail@exxodus.fedaykin.here>
In-Reply-To: <20031026064145.18F0E2A8D5@canning.wemm.org> (Peter Wemm's message of "Sat, 25 Oct 2003 23:41:45 -0700")
References:  <20031026064145.18F0E2A8D5@canning.wemm.org>

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Peter Wemm <peter@wemm.org> writes:
> Massively deep pipelines help get the MHz up, and careful optimization can
> stop it affecting frame rates.  But it blows chunks if you mispredict a
> branch in typical gcc generated code.  Or take our libc syscall stubs..
> every single one will be mispredicted because the usual case (no errors)
> has an opposite direction branch to what intel's static branch prediction
> expects.

Is there any way to teach (or trick) gcc to generate a branch which
the p4 will predict correctly?

DES
--=20
Dag-Erling Sm=F8rgrav - des@des.no



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