Date: Thu, 11 Apr 2002 13:25:05 -0400 (EDT) From: Andrew Gallatin <gallatin@cs.duke.edu> To: Denis Serenyi <dserenyi@panasas.com> Cc: freebsd-hackers@freebsd.org Subject: Re: SSE bcopy Message-ID: <15541.50929.232407.59363@grasshopper.cs.duke.edu> In-Reply-To: <5B6FF41A-4D65-11D6-9B98-003065675568@panasas.com> References: <15541.37586.404951.505010@grasshopper.cs.duke.edu> <5B6FF41A-4D65-11D6-9B98-003065675568@panasas.com>
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Denis Serenyi writes: > I don't think there will be a problem with releasing my source code. > That is, if it works and is truly a performance win :) Cool! > There are some PDF docs available on Intel's web site that have sample > code for an SSE bcopy, and give performance results (in particular, > "Block Copy Using Pentium III Streaming SIMD Extensions"). It seems to > be about 60 - 80% faster than using MMX instructions. However, when you > use SSE to store data in the destination memory location, you bypass the > processor's caches. So, if you were to touch the data soon after the > bcopy, it is no win at all. Hey, that's great! The copies I care about are in situtations where the data is not touched until much later, so the normal copy is typically a big loose because it blows out the cache.. Good luck, Drew To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message
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