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 [216.205.24.124]) by sourceware.org (Postfix) with ESMTP id BBCB43888017 for ; Tue, 6 Jul 2021 11:34:08 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.1 sourceware.org BBCB43888017 Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-117-MKNtN9ZXM_SUvJgJ0o_4ow-1; Tue, 06 Jul 2021 07:34:05 -0400 X-MC-Unique: MKNtN9ZXM_SUvJgJ0o_4ow-1 Received: from smtp.corp.redhat.com (int-mx07.intmail.prod.int.phx2.redhat.com [10.5.11.22]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 06141100CA9C; Tue, 6 Jul 2021 11:34:04 +0000 (UTC) Received: from oldenburg.str.redhat.com (ovpn-115-5.ams2.redhat.com [10.36.115.5]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 9242110016FD; Tue, 6 Jul 2021 11:33:59 +0000 (UTC) From: Florian Weimer To: Wilco Dijkstra Cc: Szabolcs Nagy via Libc-alpha , Szabolcs Nagy , Siddhesh Poyarekar Subject: Re: [PATCH] AArch64: Add hp-timing.h References: <20210630084643.GE14854@arm.com> <878s2rk9z2.fsf@oldenburg.str.redhat.com> Date: Tue, 06 Jul 2021 13:33:57 +0200 In-Reply-To: (Wilco Dijkstra's message of "Thu, 1 Jul 2021 10:21:45 +0000") Message-ID: <87sg0rhe1m.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 2.84 on 10.5.11.22 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=-7.3 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_H4, 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-alpha@sourceware.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Libc-alpha mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 06 Jul 2021 11:34:11 -0000 * Wilco Dijkstra: > Hi Florian, > >> This commit would not be entirely accurate.=C2=A0 We install and ship th= e >> benchtests, so they need to use a stable ISA (and kernel ABI). >> >> If the benchtests are like the testsuite and are not intended to be >> installed and distributed, we probably need to make downstream changes. > > Is this something distro specific? I don't see it in the GLIBC install > directory after "make install" or anywhere on my system. Looks like it. > In any case, there is no ABI change here - cntvct_el0 is always > allowed in userspace. Good to know. It's just that the performance could be problematic, right? I'm still puzzled why we can't leave the decision to the vDSO. Generic hp-timing support should do that. Thanks, Florian