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=-2.2 required=3.0 tests=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 1132FC33CAA for ; Mon, 20 Jan 2020 15:20:42 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id DA6BA2070C for ; Mon, 20 Jan 2020 15:20:41 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729030AbgATPUl (ORCPT ); Mon, 20 Jan 2020 10:20:41 -0500 Received: from gate.crashing.org ([63.228.1.57]:52061 "EHLO gate.crashing.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726626AbgATPUk (ORCPT ); Mon, 20 Jan 2020 10:20:40 -0500 Received: from gate.crashing.org (localhost.localdomain [127.0.0.1]) by gate.crashing.org (8.14.1/8.14.1) with ESMTP id 00KFJb5J002311; Mon, 20 Jan 2020 09:19:38 -0600 Received: (from segher@localhost) by gate.crashing.org (8.14.1/8.14.1/Submit) id 00KFJbq8002310; Mon, 20 Jan 2020 09:19:37 -0600 X-Authentication-Warning: gate.crashing.org: segher set sender to segher@kernel.crashing.org using -f Date: Mon, 20 Jan 2020 09:19:36 -0600 From: Segher Boessenkool To: Christophe Leroy Cc: Benjamin Herrenschmidt , Paul Mackerras , Michael Ellerman , nathanl@linux.ibm.com, arnd@arndb.de, tglx@linutronix.de, vincenzo.frascino@arm.com, luto@kernel.org, x86@kernel.org, linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-mips@vger.kernel.org Subject: Re: [RFC PATCH v4 00/11] powerpc: switch VDSO to C implementation. Message-ID: <20200120151936.GB3191@gate.crashing.org> References: <20200117085851.GS3191@gate.crashing.org> <3027b6d2-47a9-a871-7c52-050a5f9c6ab7@c-s.fr> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <3027b6d2-47a9-a871-7c52-050a5f9c6ab7@c-s.fr> User-Agent: Mutt/1.4.2.3i Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Jan 20, 2020 at 02:56:00PM +0000, Christophe Leroy wrote: > >Nice! Much better. > > > >It should be tested on more representative hardware, too, but this looks > >promising alright :-) > > mpc832x (e300c2 core) at 333 MHz: > > Before: > > gettimeofday: vdso: 235 nsec/call > clock-gettime-realtime: vdso: 244 nsec/call > > With the series: > > gettimeofday: vdso: 271 nsec/call > clock-gettime-realtime: vdso: 281 nsec/call Those are important, and degrade ~15%. That is acceptable IMO, but do you see a way to optimise this (later)? Anyway, excellent results, thanks for your persistence! Segher