Received: by 2002:ab2:6857:0:b0:1ef:ffd0:ce49 with SMTP id l23csp2978616lqp; Mon, 25 Mar 2024 15:23:36 -0700 (PDT) X-Forwarded-Encrypted: i=3; AJvYcCU1A4CfzyVpLBuSc0UyA+YSVzz7opY2ZRNctZDGp8qta2gCAe1lH7aZU96ysYSqDh9eObGLj8TfqHfrkYSMMOqhNuk01GS/ER8pKjeoDQ== X-Google-Smtp-Source: AGHT+IE9g23mqZFYlpmnV7Ody/hgnhhnfks15+kpOVM5XGgH/WZzLPJlPUcl/xDb4HbX27VUYcr5 X-Received: by 2002:a17:90a:a10d:b0:29f:be68:5cf6 with SMTP id s13-20020a17090aa10d00b0029fbe685cf6mr1067909pjp.12.1711405416016; Mon, 25 Mar 2024 15:23:36 -0700 (PDT) ARC-Seal: i=2; a=rsa-sha256; t=1711405416; cv=pass; d=google.com; s=arc-20160816; b=FMJqTXLn0EQTziYyHfqjknhJvaGmJ7ehvTXVfSDF5Bt2Z0A7ipWsRfEryHuhKzdQHG r31UHYqXAWQF5C6eekzNehqukwgPQ3gTfkpEwxHD8XSiAUO6p9/hlNijkBwDKLT9rEV4 CA92tETLOEB9hEPeuCUg47FRcv/LdW3JdX7SZP60lsoigd5FE5uFmIUgyHLD3N092rto fnLjViyzK8EIf6yHddqtKoViEaY/GVHuFrOSGR0JqquOi79agBQHmhtsWF4uh2hu8v/T B/FmJaGBJNZLK1zfpxxTXP+yuzRn7rljkUIecxHlcK1iLe7MR0KA2U7zcWHlmnjnYU1E q/yA== ARC-Message-Signature: i=2; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=subject:cc:to:from:date:references:in-reply-to:message-id :mime-version:list-unsubscribe:list-subscribe:list-id:precedence :user-agent:feedback-id:dkim-signature:dkim-signature; bh=ZOF0LllNEkKwlFc4eVFPUYe1z5e6mKp1Z3VJw8CX4q0=; fh=ntjEwlbSRPCXacwzQe5BVsAMbjebRKgMeYybu7tICgY=; b=FR9czEA/CI1RJHbGIAzdoQLYOmASseNmpvcmtDUS21YPhvyoZKs4EqhjiXoWYXdgYU 2BMaDpvd7P8YIenn1OKeMKWvkr9/1znbNnFjVePC35jzNJWo+ajsBqpwTcl8VYoohw2o 4GczFoyKDCa1zYPgHG6qOvBO3dy7d5rqHBtZ3VMiRP5glurVO6StIHytoGdNqO2WfTs8 Lt2jnoNvU4dCJDeWbFfsBZAl13BuQkFVp6kdz1Q9S0RWVpNkD842o1TQbxGvNalPzQYZ e3QwmJvC4n+ggyysrAdaTRbvAurjQFD7OH21ilcdosXtxuTlK/TYuUvK0lKWDVRAZC9E THxQ==; dara=google.com ARC-Authentication-Results: i=2; mx.google.com; dkim=pass header.i=@arndb.de header.s=fm1 header.b=fS660U1h; dkim=pass header.i=@messagingengine.com header.s=fm2 header.b=H+VPet54; arc=pass (i=1 spf=pass spfdomain=arndb.de dkim=pass dkdomain=arndb.de dkim=pass dkdomain=messagingengine.com dmarc=pass fromdomain=arndb.de); spf=pass (google.com: domain of linux-kernel+bounces-117682-linux.lists.archive=gmail.com@vger.kernel.org designates 147.75.48.161 as permitted sender) smtp.mailfrom="linux-kernel+bounces-117682-linux.lists.archive=gmail.com@vger.kernel.org"; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=arndb.de Return-Path: Received: from sy.mirrors.kernel.org (sy.mirrors.kernel.org. [147.75.48.161]) by mx.google.com with ESMTPS id e10-20020a17090a77ca00b0029deba7c7b2si8329479pjs.0.2024.03.25.15.23.35 for (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 25 Mar 2024 15:23:35 -0700 (PDT) Received-SPF: pass (google.com: domain of linux-kernel+bounces-117682-linux.lists.archive=gmail.com@vger.kernel.org designates 147.75.48.161 as permitted sender) client-ip=147.75.48.161; Authentication-Results: mx.google.com; dkim=pass header.i=@arndb.de header.s=fm1 header.b=fS660U1h; dkim=pass header.i=@messagingengine.com header.s=fm2 header.b=H+VPet54; arc=pass (i=1 spf=pass spfdomain=arndb.de dkim=pass dkdomain=arndb.de dkim=pass dkdomain=messagingengine.com dmarc=pass fromdomain=arndb.de); spf=pass (google.com: domain of linux-kernel+bounces-117682-linux.lists.archive=gmail.com@vger.kernel.org designates 147.75.48.161 as permitted sender) smtp.mailfrom="linux-kernel+bounces-117682-linux.lists.archive=gmail.com@vger.kernel.org"; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=arndb.de Received: from smtp.subspace.kernel.org (wormhole.subspace.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by sy.mirrors.kernel.org (Postfix) with ESMTPS id 1E2A0BE2EF9 for ; Mon, 25 Mar 2024 18:33:07 +0000 (UTC) Received: from localhost.localdomain (localhost.localdomain [127.0.0.1]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 334C4CA62; Mon, 25 Mar 2024 18:11:50 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=arndb.de header.i=@arndb.de header.b="fS660U1h"; dkim=pass (2048-bit key) header.d=messagingengine.com header.i=@messagingengine.com header.b="H+VPet54" Received: from wfhigh6-smtp.messagingengine.com (wfhigh6-smtp.messagingengine.com [64.147.123.157]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id A2019C136; Mon, 25 Mar 2024 18:11:47 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=64.147.123.157 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1711390309; cv=none; b=dZTvKOorZqio3pgKC7yKrCuZW0u+keft9OpwituVcIQoAjvHs5K4mLDEbe6jnNqxeQD4dN8ODdYqAzx5Q8QAlKsApWQnNWg5ZbP6DQ4avnZx15+O5YI4OgvOsPjSCVGs11St6b53fqX7xsx3lRP8dZwIAFEEOtMWlgIrFOVUTSE= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1711390309; c=relaxed/simple; bh=VWjCK0A0o0a/wQcdaC/U8lJXJ+TjP1sEl8eLKFH7/Bw=; h=MIME-Version:Message-Id:In-Reply-To:References:Date:From:To:Cc: Subject:Content-Type; b=Gt7hvCbD3xeDtds0nRlIrX9MyAlx4RctQokne1IKA4NMk6nbdNqbYQV9jbyxb64fOMidTRycW1aEYT/zKwFGZ2thWD3prC4o6kXK1OBwWxtvo/U3lpl2leew8jKs5bT3K9BpmfuSGmMyI54thpexLnN4EprLxqOcQkfcRn/jjC4= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arndb.de; spf=pass smtp.mailfrom=arndb.de; dkim=pass (2048-bit key) header.d=arndb.de header.i=@arndb.de header.b=fS660U1h; dkim=pass (2048-bit key) header.d=messagingengine.com header.i=@messagingengine.com header.b=H+VPet54; arc=none smtp.client-ip=64.147.123.157 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arndb.de Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=arndb.de Received: from compute5.internal (compute5.nyi.internal [10.202.2.45]) by mailfhigh.west.internal (Postfix) with ESMTP id 8ED3C18000A9; Mon, 25 Mar 2024 14:11:44 -0400 (EDT) Received: from imap51 ([10.202.2.101]) by compute5.internal (MEProxy); Mon, 25 Mar 2024 14:11:46 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=arndb.de; h=cc :cc:content-type:content-type:date:date:from:from:in-reply-to :in-reply-to:message-id:mime-version:references:reply-to:subject :subject:to:to; s=fm1; t=1711390304; x=1711476704; bh=ZOF0LllNEk KwlFc4eVFPUYe1z5e6mKp1Z3VJw8CX4q0=; b=fS660U1hG06tBjiG8AmosLeM/q hTeorddBxLag/Zrf1xyO/FfWBp+7Twp3Cklk/LKdRm/+lq1rQZz9dGiJIplirevn g01k8hHNfbZs67tq8XfM8O8Ir7YUNrjrjvXriGv/0GYfVW2d/UJSEmPaCNtb62IR Tya66B9hoJs/aNBwVkJ/6cmfuAYa0MVAzz8Yz5WWKsSvmk5lMo47gCl+b4WZGufs FtWbrj3AKA12vOFmE7pO9V/dgQYsntI4tYwE+ZrWjeGTpXO39SUXavwlWoX/eXod UE2RObvC29IPd5j7tndSR3+56Jy8ZSQ329r45g4ikN7lIRVEDFKyuWfRVd0w== DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d= messagingengine.com; h=cc:cc:content-type:content-type:date:date :feedback-id:feedback-id:from:from:in-reply-to:in-reply-to :message-id:mime-version:references:reply-to:subject:subject:to :to:x-me-proxy:x-me-proxy:x-me-sender:x-me-sender:x-sasl-enc; s= fm2; t=1711390304; x=1711476704; bh=ZOF0LllNEkKwlFc4eVFPUYe1z5e6 mKp1Z3VJw8CX4q0=; b=H+VPet54C3Y7QbMN4Y2/THGlKNi1RQ8lSrCen5xjBCLL GvOr72eh4g45YjvUQ/5YtYLW1AOGcmWZ+AuVmPe8BCv415DHKnogCrH0veC1RzUP 4soLf281avDmAu6o2vVquy7wX/pPOYa/cjz2mU96CdaPk3AO5uGkRgnmO8yHdpv1 yfhOd+WO9EAZPencMet7UNg86WPUFuzUNsee+X8N2L8zdMT4OB8tVDolLinZT+JR ElfnIjfZikTWSHvSEEPs4tpr0q8xAHqBHBJ/6jRuBNHG+IjH5X2s93lMvm/gPm6D rc/3lA0lJOYRCfA/QqhioypyWr5YC9LYioXWoow66w== X-ME-Sender: X-ME-Proxy-Cause: gggruggvucftvghtrhhoucdtuddrgedvledrudduuddggeelucetufdoteggodetrfdotf fvucfrrhhofhhilhgvmecuhfgrshhtofgrihhlpdfqfgfvpdfurfetoffkrfgpnffqhgen uceurghilhhouhhtmecufedttdenucesvcftvggtihhpihgvnhhtshculddquddttddmne cujfgurhepofgfggfkjghffffhvfevufgtsehttdertderredtnecuhfhrohhmpedftehr nhguuceuvghrghhmrghnnhdfuceorghrnhgusegrrhhnuggsrdguvgeqnecuggftrfgrth htvghrnhepffehueegteeihfegtefhjefgtdeugfegjeelheejueethfefgeeghfektdek teffnecuvehluhhsthgvrhfuihiivgeptdenucfrrghrrghmpehmrghilhhfrhhomheprg hrnhgusegrrhhnuggsrdguvg X-ME-Proxy: Feedback-ID: i56a14606:Fastmail Received: by mailuser.nyi.internal (Postfix, from userid 501) id 237E3B6008D; Mon, 25 Mar 2024 14:11:43 -0400 (EDT) X-Mailer: MessagingEngine.com Webmail Interface User-Agent: Cyrus-JMAP/3.11.0-alpha0-332-gdeb4194079-fm-20240319.002-gdeb41940 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Message-Id: <64804d62-1946-4cde-aea1-e8bab0860bfc@app.fastmail.com> In-Reply-To: <20240325064023.2997-1-adrian.hunter@intel.com> References: <20240325064023.2997-1-adrian.hunter@intel.com> Date: Mon, 25 Mar 2024 19:11:21 +0100 From: "Arnd Bergmann" To: "Adrian Hunter" , "Thomas Gleixner" Cc: "Peter Zijlstra" , "Dave Hansen" , "John Stultz" , "H. Peter Anvin" , "Alexander Gordeev" , "Vincenzo Frascino" , linux-s390@vger.kernel.org, x86@kernel.org, "Aneesh Kumar K.V" , "Ingo Molnar" , "Naveen N. Rao" , "Christian Borntraeger" , "Vasily Gorbik" , "Heiko Carstens" , "Nicholas Piggin" , "Borislav Petkov" , "Andy Lutomirski" , "Bjorn Helgaas" , "Anna-Maria Gleixner" , "Stephen Boyd" , "Randy Dunlap" , linux-kernel@vger.kernel.org, "Sven Schnelle" , linuxppc-dev@lists.ozlabs.org Subject: Re: [PATCH V2 00/19] timekeeping: Handle potential multiplication overflow Content-Type: text/plain On Mon, Mar 25, 2024, at 07:40, Adrian Hunter wrote: > > Extend the facility also to VDSO, dependent on new config option > GENERIC_VDSO_OVERFLOW_PROTECT which is selected by x86 only, so other > architectures are not affected. The result is a calculation that has > similar performance as before. Most machines showed performance benefit, > except Skylake-based hardware such as Intel Kaby Lake which was seen <1% > worse. I've read through the series, and this pretty much all makes sense, nice work! There are a few patches that just rearrange the local variable declarations to save a few lines, and I don't see those as an improvement, but they also don't hurt aside from distracting slightly from the real changes. Arnd