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=-5.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,MENTIONS_GIT_HOSTING,SPF_HELO_NONE,SPF_PASS 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 8F924C43613 for ; Mon, 24 Jun 2019 09:40:07 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 636B72054F for ; Mon, 24 Jun 2019 09:40:07 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728285AbfFXJkG (ORCPT ); Mon, 24 Jun 2019 05:40:06 -0400 Received: from Galois.linutronix.de ([193.142.43.55]:35467 "EHLO Galois.linutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725881AbfFXJkF (ORCPT ); Mon, 24 Jun 2019 05:40:05 -0400 Received: from p5b06daab.dip0.t-ipconnect.de ([91.6.218.171] helo=nanos) by Galois.linutronix.de with esmtpsa (TLS1.2:DHE_RSA_AES_256_CBC_SHA256:256) (Exim 4.80) (envelope-from ) id 1hfLSF-0003z0-5T; Mon, 24 Jun 2019 11:40:03 +0200 Date: Mon, 24 Jun 2019 11:40:02 +0200 (CEST) From: Thomas Gleixner To: "Sverdlin, Alexander (Nokia - DE/Ulm)" cc: "x86@kernel.org" , "linux-kernel@vger.kernel.org" , Ingo Molnar , Borislav Petkov , "H. Peter Anvin" , Jason Vas Dias , Andy Lutomirski Subject: Re: [PATCH v3 1/2] x86/vdso: Move mult and shift into struct vgtod_ts In-Reply-To: Message-ID: References: <20190605144116.28553-1-alexander.sverdlin@nokia.com> <20190605144116.28553-2-alexander.sverdlin@nokia.com> User-Agent: Alpine 2.21 (DEB 202 2017-01-01) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII X-Linutronix-Spam-Score: -1.0 X-Linutronix-Spam-Level: - X-Linutronix-Spam-Status: No , -1.0 points, 5.0 required, ALL_TRUSTED=-1,SHORTCIRCUIT=-0.0001 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Alexander, On Mon, 24 Jun 2019, Sverdlin, Alexander (Nokia - DE/Ulm) wrote: > On 23/06/2019 12:18, Thomas Gleixner wrote: > > The alternative solution for this is what Vincenzo has in his unified VDSO > > patch series: > > > > https://lkml.kernel.org/r/20190621095252.32307-1-vincenzo.frascino@arm.com > > > > It leaves the data struct unmodified and has a separate array for the raw > > clock. That does not have the side effects at all. > > > > I'm in the process of merging that series and I actually adapted your > > scheme to the new unified infrastructure where it has exactly the same > > effects as with your original patches against the x86 version. > > please let me know if I need to rework [2/2] based on some not-yet-published > branch of yours. I've pushed it out now to git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git timers/vdso The generic VDSO library has the support for RAW already with that separate array. Testing would be welcomed! Feel free to experiment with moving mult/shift again. Maybe you find a way to mitigate the effects and make it all magically faster. :) Thanks, tglx