From owner-svn-src-all@FreeBSD.ORG Tue Jan 5 13:29:24 2010 Return-Path: Delivered-To: svn-src-all@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 0A599106566B; Tue, 5 Jan 2010 13:29:24 +0000 (UTC) (envelope-from ivoras@gmail.com) Received: from ey-out-2122.google.com (ey-out-2122.google.com [74.125.78.24]) by mx1.freebsd.org (Postfix) with ESMTP id 1AEB68FC08; Tue, 5 Jan 2010 13:29:22 +0000 (UTC) Received: by ey-out-2122.google.com with SMTP id 22so542877eye.9 for ; Tue, 05 Jan 2010 05:29:19 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=domainkey-signature:mime-version:sender:received:in-reply-to :references:from:date:x-google-sender-auth:message-id:subject:to:cc :content-type:content-transfer-encoding; bh=LuUu1Iacu4Vo6QO8gUnq33sl1xrBpzBOsxsU6aRjod0=; b=xvWboMX3wknRm4Ng/Ny1bkx7G8wvoeY3SEE2xj3YPdABAzq6lck3ePygBbcxIccrv3 bBj64f1s7XdtFogOw37IJgKp24nx7O5BF4JfmCQvrMi6wVADctJoWhhEFKrmnfzeEVE6 O0jxshs08janBH9DIk7hED1THPUWhL1EEvG+c= DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=mime-version:sender:in-reply-to:references:from:date :x-google-sender-auth:message-id:subject:to:cc:content-type :content-transfer-encoding; b=xVP3/r1brXnTSLrp1Q2R2BIHC4t6HiWvJI6t2/G/gz0S5t9EXAeqjCRgVd27tjc0vq 3xi9WoGRxDeBom03hoVjCadyqJ6hGR9vH/N5ZN/aMUetGl625qp9+6Ayj1AObTTI0h3R ickinRNANhmNKnnq46X+SFaebPbVLNvNRzHRY= MIME-Version: 1.0 Sender: ivoras@gmail.com Received: by 10.216.90.14 with SMTP id d14mr2074711wef.30.1262698159486; Tue, 05 Jan 2010 05:29:19 -0800 (PST) In-Reply-To: <201001050206.o05265Ln053910@svn.freebsd.org> References: <201001050206.o05265Ln053910@svn.freebsd.org> From: Ivan Voras Date: Tue, 5 Jan 2010 14:28:59 +0100 X-Google-Sender-Auth: 7a1f072c25cc3d90 Message-ID: <9bbcef731001050528k5b46b8ect2f9576f7b47e563a@mail.gmail.com> To: Alexander Motin Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable Cc: svn-src-head@freebsd.org, svn-src-all@freebsd.org, src-committers@freebsd.org Subject: Re: svn commit: r201545 - head/sys/geom/raid3 X-BeenThere: svn-src-all@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: "SVN commit messages for the entire src tree \(except for " user" and " projects" \)" List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 05 Jan 2010 13:29:24 -0000 2010/1/5 Alexander Motin : > Author: mav > Date: Tue Jan =C2=A05 02:06:05 2010 > New Revision: 201545 > URL: http://svn.freebsd.org/changeset/base/201545 > > Log: > =C2=A0Slightly optimize XOR calculation. Linux has an interesting approach to RAID XOR operations - they calculate at boot time which method is faster, from a set of i386, MMX, SSE and the like and then use it for what appears to be every context requiring fast XORs. E.g. http://fxr.watson.org/fxr/source/arch/x86/include/asm/xor_64.h?v=3Dlinux-2.= 6 (I know SIMD instructions would require a FP-enabled kernel, I'm just pointing out an interesting idea)