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=-2.3 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,USER_AGENT_SANE_1 autolearn=no 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 48FF5C33CB1 for ; Fri, 17 Jan 2020 08:59:55 +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 173F02082F for ; Fri, 17 Jan 2020 08:59:55 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="gu1usfTM" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 173F02082F Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=kernel.crashing.org 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:References: Message-ID:Subject:To:From:Date:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=vwD1IMpp3PDm+o1RDND5+gl0cYz5wRxqhn8GBahWGUI=; b=gu1usfTMumPENW MpNPfNp84vUJae5fALJLajB/eUfcu1wsQG7EC8LHcl9FYdy0aazQz8AcLvMoapVq9TRMeDbdqGXNR g63h722iN/4SAc7CRyQdIx8gNFbSO9JoeY+ZX7ze7oKsTu9uhp2kdYDviOxFDKU6wecz0is2mDjf4 B0ZRTw8SdMcoI7ETXMM3ytiqVGDYmybnEEXsSui0gWetOroIM2u0fFqk/c/2UJnyBK+CdRsPHhnBm xIr/5OPi0BVryzpiGb7lX90mfSFBoJEpa/TaNEVO4njHg1EKms+SS+qsKn+lw6xJ76EqyZXW+kpN6 nfdrVgLsPPOy8a6lNrMg==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1isNTj-0006uQ-BK; Fri, 17 Jan 2020 08:59:43 +0000 Received: from gate.crashing.org ([63.228.1.57]) by bombadil.infradead.org with esmtps (Exim 4.92.3 #3 (Red Hat Linux)) id 1isNTb-0006iB-Bo for linux-arm-kernel@lists.infradead.org; Fri, 17 Jan 2020 08:59:41 +0000 Received: from gate.crashing.org (localhost.localdomain [127.0.0.1]) by gate.crashing.org (8.14.1/8.14.1) with ESMTP id 00H8ws29002697; Fri, 17 Jan 2020 02:58:54 -0600 Received: (from segher@localhost) by gate.crashing.org (8.14.1/8.14.1/Submit) id 00H8wpV1002692; Fri, 17 Jan 2020 02:58:51 -0600 X-Authentication-Warning: gate.crashing.org: segher set sender to segher@kernel.crashing.org using -f Date: Fri, 17 Jan 2020 02:58:51 -0600 From: Segher Boessenkool To: Christophe Leroy Subject: Re: [RFC PATCH v4 00/11] powerpc: switch VDSO to C implementation. Message-ID: <20200117085851.GS3191@gate.crashing.org> References: Mime-Version: 1.0 Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.4.2.3i X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20200117_005935_543900_402F86B9 X-CRM114-Status: UNSURE ( 9.36 ) X-CRM114-Notice: Please train this message. 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: nathanl@linux.ibm.com, arnd@arndb.de, Benjamin Herrenschmidt , x86@kernel.org, linux-kernel@vger.kernel.org, linux-mips@vger.kernel.org, Paul Mackerras , luto@kernel.org, Michael Ellerman , tglx@linutronix.de, vincenzo.frascino@arm.com, linuxppc-dev@lists.ozlabs.org, 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 Hi! On Thu, Jan 16, 2020 at 05:58:24PM +0000, Christophe Leroy wrote: > On a powerpc8xx, with current powerpc/32 ASM VDSO: > > gettimeofday: vdso: 907 nsec/call > clock-getres-realtime: vdso: 484 nsec/call > clock-gettime-realtime: vdso: 899 nsec/call > > The first patch adds VDSO generic C support without any changes to common code. > Performance is as follows: > > gettimeofday: vdso: 1211 nsec/call > clock-getres-realtime: vdso: 722 nsec/call > clock-gettime-realtime: vdso: 1216 nsec/call > > Then a few changes in the common code have allowed performance improvement. At > the end of the series we have: > > gettimeofday: vdso: 974 nsec/call > clock-getres-realtime: vdso: 545 nsec/call > clock-gettime-realtime: vdso: 941 nsec/call > > The final result is rather close to pure ASM VDSO: > * 7% more on gettimeofday (9 cycles) > * 5% more on clock-gettime-realtime (6 cycles) > * 12% more on clock-getres-realtime (8 cycles) Nice! Much better. It should be tested on more representative hardware, too, but this looks promising alright :-) Segher _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel