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=-7.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,MENTIONS_GIT_HOSTING,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 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 D7D2ECA9EBC for ; Thu, 24 Oct 2019 13:12:38 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id B82F020659 for ; Thu, 24 Oct 2019 13:12:38 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2502410AbfJXNMh (ORCPT ); Thu, 24 Oct 2019 09:12:37 -0400 Received: from foss.arm.com ([217.140.110.172]:50898 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2390361AbfJXNMh (ORCPT ); Thu, 24 Oct 2019 09:12:37 -0400 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 90865C8F; Thu, 24 Oct 2019 06:12:21 -0700 (PDT) Received: from [10.37.9.200] (unknown [10.37.9.200]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 103823F71A; Thu, 24 Oct 2019 06:12:14 -0700 (PDT) Subject: Re: [PATCHv7 18/33] lib/vdso: Add unlikely() hint into vdso_read_begin() From: Vincenzo Frascino To: Andrei Vagin Cc: Dmitry Safonov , linux-kernel@vger.kernel.org, Dmitry Safonov <0x7f454c46@gmail.com>, Adrian Reber , Andrei Vagin , Andy Lutomirski , Arnd Bergmann , Christian Brauner , Cyrill Gorcunov , "Eric W. Biederman" , "H. Peter Anvin" , Ingo Molnar , Jann Horn , Jeff Dike , Oleg Nesterov , Pavel Emelyanov , Shuah Khan , Thomas Gleixner , containers@lists.linux-foundation.org, criu@openvz.org, linux-api@vger.kernel.org, x86@kernel.org References: <20191011012341.846266-1-dima@arista.com> <20191011012341.846266-19-dima@arista.com> <100f6921-9081-7eb0-7acc-f10cfb647c21@arm.com> <20191024061311.GA4541@gmail.com> <9aa9857e-ee1c-0117-bfcb-45fc6bcab866@arm.com> Message-ID: Date: Thu, 24 Oct 2019 14:14:19 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.9.0 MIME-Version: 1.0 In-Reply-To: <9aa9857e-ee1c-0117-bfcb-45fc6bcab866@arm.com> Content-Type: text/plain; charset=koi8-r Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Andrei, On 10/24/19 10:30 AM, Vincenzo Frascino wrote: [...] >> Here is my test: >> https://github.com/avagin/vdso-perf >> >> It is calling clock_gettime() in a loop for three seconds and then >> reports a number of iterations. >> > > I am happy to run the test on arm64 and provide some results. > Please find below the results: clock | before | after | diff ================================================== monotonic 17326692 17951770 3.6% monotonic-coarse 43624027 44215292 1.3% monotonic-raw 17541809 17554932 0.1% boottime 17334982 17954361 3.5% The improvement for arm64 for monotonic and boottime is around 3.5%. I created a pull request on github to send to you back the changes I had to do to vdso-perf to cross-compile it on arm64 [1]. [1] https://github.com/avagin/vdso-perf/pull/1 >> Thanks, >> Andrei >> > -- Regards, Vincenzo