From owner-freebsd-hackers Thu Apr 11 10:25:40 2002 Delivered-To: freebsd-hackers@freebsd.org Received: from duke.cs.duke.edu (duke.cs.duke.edu [152.3.140.1]) by hub.freebsd.org (Postfix) with ESMTP id EB62737B416 for ; Thu, 11 Apr 2002 10:25:35 -0700 (PDT) Received: from grasshopper.cs.duke.edu (grasshopper.cs.duke.edu [152.3.145.30]) by duke.cs.duke.edu (8.9.3/8.9.3) with ESMTP id NAA13459; Thu, 11 Apr 2002 13:25:35 -0400 (EDT) Received: (from gallatin@localhost) by grasshopper.cs.duke.edu (8.11.6/8.9.1) id g3BHP5U34402; Thu, 11 Apr 2002 13:25:05 -0400 (EDT) (envelope-from gallatin@cs.duke.edu) From: Andrew Gallatin MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Message-ID: <15541.50929.232407.59363@grasshopper.cs.duke.edu> Date: Thu, 11 Apr 2002 13:25:05 -0400 (EDT) To: Denis Serenyi Cc: freebsd-hackers@freebsd.org Subject: Re: SSE bcopy 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> X-Mailer: VM 6.75 under 21.1 (patch 12) "Channel Islands" XEmacs Lucid Sender: owner-freebsd-hackers@FreeBSD.ORG Precedence: bulk List-ID: List-Archive: (Web Archive) List-Help: (List Instructions) List-Subscribe: List-Unsubscribe: X-Loop: FreeBSD.ORG 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