From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) by sourceware.org (Postfix) with ESMTPS id 36FD13858020 for ; Fri, 25 Feb 2022 14:01:31 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.1 sourceware.org 36FD13858020 Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-278-JjIljEn8O2a6PkQirZaSmg-1; Fri, 25 Feb 2022 09:01:14 -0500 X-MC-Unique: JjIljEn8O2a6PkQirZaSmg-1 Received: from smtp.corp.redhat.com (int-mx01.intmail.prod.int.phx2.redhat.com [10.5.11.11]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 6067F180FD73; Fri, 25 Feb 2022 14:01:13 +0000 (UTC) Received: from oldenburg.str.redhat.com (unknown [10.39.193.76]) by smtp.corp.redhat.com (Postfix) with ESMTPS id E70447A55D; Fri, 25 Feb 2022 14:01:10 +0000 (UTC) From: Florian Weimer To: Xi Ruoyao via Gcc-help Subject: Re: Libatomic 16B References: <6349834d9ea31f579b04ba9215b6449ce13f008e.camel@mengyan1223.wang> <1bb8ab09556727917d07ec31683996bb7e493fa6.camel@mengyan1223.wang> <20220224201334.GQ614@gate.crashing.org> <37e3b73aba3fd6dd6c109d0a06680af3577c4b41.camel@mengyan1223.wang> Date: Fri, 25 Feb 2022 15:01:08 +0100 In-Reply-To: <37e3b73aba3fd6dd6c109d0a06680af3577c4b41.camel@mengyan1223.wang> (Xi Ruoyao via Gcc-help's message of "Fri, 25 Feb 2022 16:48:43 +0800") Message-ID: <874k4nvye3.fsf@oldenburg.str.redhat.com> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/27.2 (gnu/linux) MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.11 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain X-Spam-Status: No, score=-6.1 required=5.0 tests=BAYES_00, DKIMWL_WL_HIGH, DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, DKIM_VALID_EF, RCVD_IN_DNSWL_LOW, RCVD_IN_MSPIKE_H5, RCVD_IN_MSPIKE_WL, SPF_HELO_NONE, SPF_NONE, TXREP, T_SCC_BODY_TEXT_LINE autolearn=ham autolearn_force=no version=3.4.4 X-Spam-Checker-Version: SpamAssassin 3.4.4 (2020-01-24) on server2.sourceware.org X-BeenThere: gcc-help@gcc.gnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Gcc-help mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 25 Feb 2022 14:01:32 -0000 * Xi Ruoyao via Gcc-help: > On Fri, 2022-02-25 at 09:35 +0100, Stefan Ring via Gcc-help wrote: >> On Thu, Feb 24, 2022 at 9:39 PM Satish Vasudeva via Gcc-help >> wrote: >> > >> > Please let into this intel architecture manual , section 8.1.1 >> > >> > https://cdrdv2.intel.com/v1/dl/getContent/671190 >> > >> > I think Intel claims 16B operations are atomic , unless I am missing >> > something. >> >> Interesting. This seems to be a somewhat recent addition, and the >> mailing list discussion linked to above predates it. Coincidentally, I >> pulled a copy of the Intel manuals at almost exactly the same time as >> this discussion, and sure enough, it does not yet contain the >> paragraph about 16 byte operations. > > It seems an addition in Dec 2021 revision: > https://cdrdv2.intel.com/v1/dl/getContent/671294 > > Create an issue in bugzilla then? Yes please. I should have read the whole thread first. 8-) The AMD manual doesn't say this yet, so any optimization needs to be restricted to Intel CPUs for now. I'll reach out to AMD to get clarification. Thanks, Florian