From owner-sc22wg5+sc22wg5-dom8=www.open-std.org@open-std.org Sat Mar 30 14:22:05 2013 Return-Path: X-Original-To: sc22wg5-dom8 Delivered-To: sc22wg5-dom8@www.open-std.org Received: by www.open-std.org (Postfix, from userid 521) id EB394356DE6; Sat, 30 Mar 2013 14:22:05 +0100 (CET) Delivered-To: sc22wg5@open-std.org Received: from postout.lrz.de (postout.lrz.de [129.187.254.115]) by www.open-std.org (Postfix) with ESMTP id 3B923356DD8 for ; Sat, 30 Mar 2013 14:22:01 +0100 (CET) Received: from lxmhs51.srv.lrz.de (localhost [127.0.0.1]) by postout3.mail.lrz.de (Postfix) with ESMTP id 1E37420096; Sat, 30 Mar 2013 14:22:01 +0100 (CET) X-Virus-Scanned: by amavisd-new at lrz.de in lxmhs51.srv.lrz.de Received: from postout3.mail.lrz.de ([127.0.0.1]) by lxmhs51.srv.lrz.de (lxmhs51.srv.lrz.de [127.0.0.1]) (amavisd-new, port 20024) with LMTP id v1uIEacZ0RiD; Sat, 30 Mar 2013 14:22:00 +0100 (CET) Received: from BADWLRZ-SWHBT2.ads.mwn.de (BADWLRZ-SWHBT2.ads.mwn.de [IPv6:2001:4ca0:0:108::126]) (using TLSv1 with cipher AES128-SHA (128/128 bits)) (Client CN "BADWLRZ-SWHBT2", Issuer "BADWLRZ-SWHBT2" (not verified)) by postout3.mail.lrz.de (Postfix) with ESMTPS id 7A21620095; Sat, 30 Mar 2013 14:22:00 +0100 (CET) Received: from BADWLRZ-SWMBX11.ads.mwn.de ([fe80::6de5:ff8b:1900:b1a1]) by BADWLRZ-SWHBT2.ads.mwn.de ([fe80::5951:9dc3:7b2b:14ba%13]) with mapi id 14.01.0438.000; Sat, 30 Mar 2013 14:21:51 +0100 From: "Bader, Reinhold" To: "longb@cray.com" , sc22wg5 Subject: AW: (SC22WG5.4946) (j3.2006) AW: WG5 ballot on first draft TS 18508, Additional Parallel Features in Fortran (Update) Thread-Topic: (SC22WG5.4946) (j3.2006) AW: WG5 ballot on first draft TS 18508, Additional Parallel Features in Fortran (Update) Thread-Index: AQHOLNVFctqLLZJl1kac+GJEX2XgPpi+N45Q Date: Sat, 30 Mar 2013 13:21:51 +0000 Message-ID: <166ED263DF83324D9A3BA67FB6772B2B59F2B59A@BADWLRZ-SWMBX11.ads.mwn.de> References: <20130329104945.2C28A356BB3@www.open-std.org> <20130329232930.A368A356DC2@www.open-std.org> In-Reply-To: <20130329232930.A368A356DC2@www.open-std.org> Accept-Language: de-DE, en-US Content-Language: de-DE X-MS-Has-Attach: X-MS-TNEF-Correlator: x-originating-ip: [129.187.48.197] Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 Sender: owner-sc22wg5@open-std.org Precedence: bulk > -----Urspr=FCngliche Nachricht----- > Von: owner-sc22wg5@open-std.org [mailto:owner-sc22wg5@open-std.org] Im > Auftrag von Bill Long > Gesendet: Samstag, 30. M=E4rz 2013 00:30 > An: sc22wg5 > Betreff: (SC22WG5.4946) (j3.2006) AW: WG5 ballot on first draft TS 18508, > Additional Parallel Features in Fortran (Update) >=20 >=20 >=20 > On 3/29/13 5:49 AM, Bader, Reinhold wrote: > > (D.1) Add CO_MULT for efficiency > > > > Nowadays interconnects have support for offloading certain operations > > to the infrastructure (e.g., FCA aka "fabric collective acceleration"), > > thereby considerably improving performance. > > However, it appears unlikely that the relatively general CO_REDUCE > > facility would be able to support this facility. Therefore, it may > > be desirable to also provide a CO_MULT collective for arguments of > > numeric type that supports multiplicative reductions, in order to > > obtain the same level of performance for all basic numeric operations. >=20 > If we added this, it would be CO_PRODUCT since the local one is PRODUCT. > The previous proposal had CO_PRODUCT. It was removed because the > corresponding MPI_REDUCE for that operation almost never occurs in real > codes. Is there any common usage of this operation? Also, is there > hardware support in network hardware for a multiply reduction? According to Mellanox' FCA documentation, all commonly used numeric data ty= pes (except complex) support MPI_Reduce and MPI_Allreduce; I would assume that this includes the argume= nt variants MPI_SUM and MPI_PRODUCT.=20 I must however admit that a significant (if not the bulk) part of the FCA o= ptimization is concerned with topology awareness,=20 so will also be applicable to the general reduction facility.=20 Regards Reinhold >=20 > Cheers, > Bill >=20 >=20 > -- > Bill Long longb@cray.com > Fortran Technical Support & voice: 651-605-9024 > Bioinformatics Software Development fax: 651-605-9142 > Cray Inc./Cray Plaza, Suite 210/380 Jackson St./St. Paul, MN 55101 >=20