From owner-freebsd-bugs@freebsd.org Wed Mar 29 04:26:41 2017 Return-Path: Delivered-To: freebsd-bugs@mailman.ysv.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) by mailman.ysv.freebsd.org (Postfix) with ESMTP id 4C0B5D23E9D for ; Wed, 29 Mar 2017 04:26:41 +0000 (UTC) (envelope-from bugzilla-noreply@freebsd.org) Received: from kenobi.freebsd.org (kenobi.freebsd.org [IPv6:2001:1900:2254:206a::16:76]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client did not present a certificate) by mx1.freebsd.org (Postfix) with ESMTPS id 23BBC65E85 for ; Wed, 29 Mar 2017 04:26:41 +0000 (UTC) (envelope-from bugzilla-noreply@freebsd.org) Received: from bugs.freebsd.org ([127.0.1.118]) by kenobi.freebsd.org (8.15.2/8.15.2) with ESMTP id v2T4Qf5o006016 for ; Wed, 29 Mar 2017 04:26:41 GMT (envelope-from bugzilla-noreply@freebsd.org) From: bugzilla-noreply@freebsd.org To: freebsd-bugs@FreeBSD.org Subject: [Bug 218203] Implement AVX2 accelerated Fletcher algorithms Date: Wed, 29 Mar 2017 04:26:41 +0000 X-Bugzilla-Reason: AssignedTo X-Bugzilla-Type: new X-Bugzilla-Watch-Reason: None X-Bugzilla-Product: Base System X-Bugzilla-Component: kern X-Bugzilla-Version: CURRENT X-Bugzilla-Keywords: X-Bugzilla-Severity: Affects Only Me X-Bugzilla-Who: kungfujesus06@gmail.com X-Bugzilla-Status: New X-Bugzilla-Resolution: X-Bugzilla-Priority: --- X-Bugzilla-Assigned-To: freebsd-bugs@FreeBSD.org X-Bugzilla-Flags: X-Bugzilla-Changed-Fields: bug_id short_desc product version rep_platform op_sys bug_status bug_severity priority component assigned_to reporter Message-ID: Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable X-Bugzilla-URL: https://bugs.freebsd.org/bugzilla/ Auto-Submitted: auto-generated MIME-Version: 1.0 X-BeenThere: freebsd-bugs@freebsd.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: Bug reports List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 29 Mar 2017 04:26:41 -0000 https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=3D218203 Bug ID: 218203 Summary: Implement AVX2 accelerated Fletcher algorithms Product: Base System Version: CURRENT Hardware: amd64 OS: Any Status: New Severity: Affects Only Me Priority: --- Component: kern Assignee: freebsd-bugs@FreeBSD.org Reporter: kungfujesus06@gmail.com Intel has published a pretty straight forward implementation of Fletcher4 leveraging AVX2 instructions:=20=20 https://software.intel.com/en-us/articles/fast-computation-of-fletcher-chec= ksums I was able to use this white paper and compiler intrinsics to build a rudimentary version that's nearly twice as fast. It is feasible to swap out the existing scalar and portable implementation for this faster variant sim= ilar to the way Linux offers SIMD accelerated versions of cryptographic and hash= ing routines within their kernel.=20=20 As a matter of fact, zfsonlinux is already doing this: https://github.com/zfsonlinux/zfs/tree/482cd9ee69e88710e9241fac220501ea4e10= 1d19/module/zcommon While I understand the desire to remain close to the reference ZFS implementation with Illumos and maybe there doesn't need to be quite that m= any versions of fletcher4 (they do a superscalar version that presumably tries = to take advantage of Out-of-Order execution - hoping the microarchitecture can schedule the instructions efficiently by noticing the lack of data dependencies), it does seem silly to ignore a working implementation that is measurably faster for CPUs that support it. It has even been backported to SSSE3 instructions: https://github.com/zfsonlinux/zfs/blob/482cd9ee69e88710e9241fac220501ea4e10= 1d19/module/zcommon/zfs_fletcher_sse.c --=20 You are receiving this mail because: You are the assignee for the bug.=