From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-0.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 11075C433F5 for ; Sat, 1 Sep 2018 09:33:44 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id ADC0820841 for ; Sat, 1 Sep 2018 09:33:43 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org ADC0820841 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727357AbeIANpE (ORCPT ); Sat, 1 Sep 2018 09:45:04 -0400 Received: from mx3-rdu2.redhat.com ([66.187.233.73]:34322 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1725973AbeIANpE (ORCPT ); Sat, 1 Sep 2018 09:45:04 -0400 Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.rdu2.redhat.com [10.11.54.4]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id DDB42804B4DB; Sat, 1 Sep 2018 09:33:40 +0000 (UTC) Received: from oldenburg.str.redhat.com (ovpn-116-36.ams2.redhat.com [10.36.116.36]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 694DB2026D66; Sat, 1 Sep 2018 09:33:39 +0000 (UTC) Subject: Re: [PATCH v3] x86/vdso: Handle clock_gettime(CLOCK_TAI) in vDSO To: Andy Lutomirski , Matt Rickard Cc: Thomas Gleixner , Stephen Boyd , John Stultz , X86 ML , LKML References: <20180901015935.CCF0B18E20A9@virtux64.softrans.com.au> From: Florian Weimer Message-ID: <0a94774a-6b8b-2014-93e6-131af9c319a6@redhat.com> Date: Sat, 1 Sep 2018 11:33:38 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.9.1 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit X-Scanned-By: MIMEDefang 2.78 on 10.11.54.4 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.11.55.8]); Sat, 01 Sep 2018 09:33:40 +0000 (UTC) X-Greylist: inspected by milter-greylist-4.5.16 (mx1.redhat.com [10.11.55.8]); Sat, 01 Sep 2018 09:33:40 +0000 (UTC) for IP:'10.11.54.4' DOMAIN:'int-mx04.intmail.prod.int.rdu2.redhat.com' HELO:'smtp.corp.redhat.com' FROM:'fweimer@redhat.com' RCPT:'' Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 09/01/2018 05:39 AM, Andy Lutomirski wrote: > Florian, do you think > glibc would be willing to add some magic to turn > clock_gettime(CLOCK_MONOTONIC, t) into > __vdso_clock_gettime_monotonic(t) when CLOCK_MONOTONIC is a constant? What's the goal here? Turn the indirect call/conditional jump/indirect call sequence into a single indirect call, purely for performance reasons? Thanks, Florian