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 [170.10.129.124]) by sourceware.org (Postfix) with ESMTPS id 15EDB3858D28 for ; Wed, 15 Dec 2021 20:41:04 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.1 sourceware.org 15EDB3858D28 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-441-5YPThhO6M42dn3j_CHY3QA-1; Wed, 15 Dec 2021 15:40:55 -0500 X-MC-Unique: 5YPThhO6M42dn3j_CHY3QA-1 Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.phx2.redhat.com [10.5.11.14]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 5107C85B660; Wed, 15 Dec 2021 20:40:54 +0000 (UTC) Received: from oldenburg.str.redhat.com (unknown [10.2.17.223]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 7B2E15ED4B; Wed, 15 Dec 2021 20:40:53 +0000 (UTC) From: Florian Weimer To: "Miller, Tim via Libc-help" Subject: Re: Build glibc for aarch64 with C-only versions of memcpy? References: <52DC392C-C51F-41DF-9120-574221C873A8@amazon.com> Date: Wed, 15 Dec 2021 21:40:51 +0100 In-Reply-To: <52DC392C-C51F-41DF-9120-574221C873A8@amazon.com> (Tim via Libc-help Miller's message of "Wed, 15 Dec 2021 20:31:55 +0000") Message-ID: <87lf0lppnw.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 10.5.11.14 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable X-Spam-Status: No, score=-6.5 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_H3, RCVD_IN_MSPIKE_WL, SPF_HELO_NONE, SPF_NONE, TXREP 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: libc-help@sourceware.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Libc-help mailing list List-Unsubscribe: , List-Archive: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 15 Dec 2021 20:41:05 -0000 * Tim via Libc-help Miller: > I am doing some software profiling on an aarch64 system, and I=E2=80=99m = using > the Linux perf tool. The problem I=E2=80=99m running into is that > =E2=80=9C__GI___memcpy_simd=E2=80=9D keeps showing up as the function wit= h the most > CPU usage. This sounds like a perf bug. Surely it can look at the LR register and see where the call is coming from? If it shows up so high in profiles, I suggest to attach a debugger and see if you can get to it to stop in the memcpy call, and take things from there. Thanks, Florian