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=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,URIBL_BLOCKED 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 856C5C43613 for ; Fri, 21 Jun 2019 09:17:10 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 5E5E521530 for ; Fri, 21 Jun 2019 09:17:10 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="dHDs08NO" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 5E5E521530 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=arm.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20170209; h=Sender: Content-Transfer-Encoding:Content-Type:Cc:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:Date: Message-ID:From:References:To:Subject:Reply-To:Content-ID:Content-Description :Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=LdTCvTw3p2MOffCQHeHIFE58Txk6s1mbMgtWKASrsPQ=; b=dHDs08NOCB78I/ ZljsFmMjMpeuCFoPHToMrI0Moc+TZOITat3w267r1qaCFJCJWlv9VHNDHK1kZP/ufWS3UIevd5JdL wtbWjLUd2021PmiJI1+0glTItFx/KpV7EcXshQajURie3jhXCPo2n0Xa4pB/zoZvxkt5qV+d48b7c TVpUeTpAO67ZYQUnm5BpiUbXA9Idb+WMu9ynBoKkpuOJpCHEa+ej+O1X7DVyj+a91FzQpviz46XN8 q4yyITHX9LqGd3Xg2yp7dU0866eTAi7rK95jFv4WGPFAOKi5HVWbUPc/6HotDjpx501szNz5Khhlb Ytt48IhdNsSUUhWbsDqw==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.92 #3 (Red Hat Linux)) id 1heFfM-0002xZ-Mm; Fri, 21 Jun 2019 09:17:04 +0000 Received: from foss.arm.com ([217.140.110.172]) by bombadil.infradead.org with esmtp (Exim 4.92 #3 (Red Hat Linux)) id 1heFaW-0007LU-N3 for linux-arm-kernel@lists.infradead.org; Fri, 21 Jun 2019 09:12:07 +0000 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 98C30360; Fri, 21 Jun 2019 02:12:02 -0700 (PDT) Received: from [10.1.196.72] (e119884-lin.cambridge.arm.com [10.1.196.72]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 3041B3F246; Fri, 21 Jun 2019 02:12:00 -0700 (PDT) Subject: Re: [PATCH v6 00/19] Unify vDSOs across more architectures To: Andre Przywara References: <20190530141531.43462-1-vincenzo.frascino@arm.com> <20190620172746.7f92cb14@donnerap.cambridge.arm.com> From: Vincenzo Frascino Message-ID: <40c3e4e9-96d3-f940-f5cb-ed97762ef9b0@arm.com> Date: Fri, 21 Jun 2019 10:11:58 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.7.0 MIME-Version: 1.0 In-Reply-To: <20190620172746.7f92cb14@donnerap.cambridge.arm.com> Content-Language: en-US X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20190621_021204_992551_18954478 X-CRM114-Status: GOOD ( 18.50 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: linux-arch@vger.kernel.org, Peter Collingbourne , Arnd Bergmann , Huw Davies , Catalin Marinas , Daniel Lezcano , Will Deacon , linux-kernel@vger.kernel.org, Ralf Baechle , linux-mips@vger.kernel.org, Paul Burton , linux-kselftest@vger.kernel.org, Rasmus Villemoes , Russell King , Dmitry Safonov <0x7f454c46@gmail.com>, Mark Salyzyn , Shuah Khan , Thomas Gleixner , linux-arm-kernel@lists.infradead.org Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org On 20/06/2019 17:27, Andre Przywara wrote: > On Thu, 30 May 2019 15:15:12 +0100 > Vincenzo Frascino wrote: > > Hi, > >> vDSO (virtual dynamic shared object) is a mechanism that the Linux >> kernel provides as an alternative to system calls to reduce where >> possible the costs in terms of cycles. >> [ ... ] >> The porting has been benchmarked and the performance results are >> provided as part of this cover letter. > > I can't reveal the absolute numbers here, but vdsotest-bench gives me > quite some performance gain on my board here ("time needed on v6" divided > by "time needed on 5.2-rc1", so smaller percentages are better): > clock-gettime-monotonic: 23 % > clock-gettime-monotonic-raw: 30 % > clock-gettime-tai: 5 % > clock-getres-tai: 5 % > clock-gettime-boottime: 5 % > clock-getres-boottime: 5 % > clock-gettime-realtime: 25 % > gettimeofday: 26 % > The other numbers stayed the same or differed by just 1 ns, which seems to > be within the margin of error, as repeated runs on the same kernel suggest. > The 5% numbers are of course those were we went from a syscall-only to the > newly added arm64 VDSO implementation, but even the other calls improved > by a factor of 3 or more. > > Sounds like a strong indicator that this is a good thing to have. > > Not sure if "running some benchmark a couple of times on a single machine" > qualifies for this, but I guess it means: > > Tested-by: Andre Przywara > Thanks Andre, it sounds great! I will add your tag as well to my patches. > Cheers, > Andre. > -- Regards, Vincenzo _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel