From mboxrd@z Thu Jan 1 00:00:00 1970 From: Vincenzo Frascino Subject: Re: [PATCHv7 18/33] lib/vdso: Add unlikely() hint into vdso_read_begin() Date: Thu, 24 Oct 2019 14:14:19 +0100 Message-ID: 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> Mime-Version: 1.0 Content-Type: text/plain; charset=koi8-r Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <9aa9857e-ee1c-0117-bfcb-45fc6bcab866@arm.com> Content-Language: en-US Sender: linux-kernel-owner@vger.kernel.org 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 List-Id: linux-api@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