Date: Fri, 27 Jul 2012 17:36:19 +1000 (EST) From: Bruce Evans <brde@optusnet.com.au> To: Luigi Rizzo <rizzo@iet.unipi.it> Cc: svn-src-head@FreeBSD.org, Roman Divacky <rdivacky@FreeBSD.org>, src-committers@FreeBSD.org, Luigi Rizzo <luigi@FreeBSD.org>, svn-src-all@FreeBSD.org Subject: Re: svn commit: r238818 - head/sys/dev/netmap Message-ID: <20120727173155.A5046@besplex.bde.org> In-Reply-To: <20120727063813.GB49988@onelab2.iet.unipi.it> References: <201207262137.q6QLbwGi028133@svn.freebsd.org> <20120726213959.GA12908@freebsd.org> <20120727063813.GB49988@onelab2.iet.unipi.it>
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On Fri, 27 Jul 2012, Luigi Rizzo wrote: > On Thu, Jul 26, 2012 at 11:39:59PM +0200, Roman Divacky wrote: >> Why dont you use __builtin_prefetch() ? > > ignorance :) > > thanks for the pointer, i'll look at it. > i suppose it works for clang too ? Even gcc-3.3.1 has it (I expected it not to). And it works quite well (defaults to nothing from -mi386, and gives prefetcht0 for -march=athlon-xp and later). Other builtins that I have tried didn't work so well (IIRC, many generate a call to a library function instead of nothing, when the CPU or compiler doesn't really support them). Bruce
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