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=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS 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 65D90C4332D for ; Fri, 20 Mar 2020 09:57:40 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 3611720722 for ; Fri, 20 Mar 2020 09:57:40 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727120AbgCTJ5j (ORCPT ); Fri, 20 Mar 2020 05:57:39 -0400 Received: from Galois.linutronix.de ([193.142.43.55]:35116 "EHLO Galois.linutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726527AbgCTJ5i (ORCPT ); Fri, 20 Mar 2020 05:57:38 -0400 Received: from p5de0bf0b.dip0.t-ipconnect.de ([93.224.191.11] helo=nanos.tec.linutronix.de) by Galois.linutronix.de with esmtpsa (TLS1.2:DHE_RSA_AES_256_CBC_SHA256:256) (Exim 4.80) (envelope-from ) id 1jFEPC-0001Cs-H1; Fri, 20 Mar 2020 10:57:30 +0100 Received: by nanos.tec.linutronix.de (Postfix, from userid 1000) id 7A509100375; Fri, 20 Mar 2020 10:57:29 +0100 (CET) From: Thomas Gleixner To: Kyung Min Park , x86@kernel.org, linux-kernel@vger.kernel.org Cc: mingo@redhat.com, hpa@zytor.com, gregkh@linuxfoundation.org, ak@linux.intel.com, tony.luck@intel.com, ashok.raj@intel.com, ravi.v.shankar@intel.com, fenghua.yu@intel.com, kyung.min.park@intel.com Subject: Re: [PATCH v2 0/2] x86/delay: Introduce TPAUSE instruction In-Reply-To: <1584677604-32707-1-git-send-email-kyung.min.park@intel.com> References: <1584677604-32707-1-git-send-email-kyung.min.park@intel.com> Date: Fri, 20 Mar 2020 10:57:29 +0100 Message-ID: <87a74b4ad2.fsf@nanos.tec.linutronix.de> MIME-Version: 1.0 Content-Type: text/plain 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 Hi! Kyung Min Park writes: > Intel processors that support the WAITPKG feature implement > the TPAUSE instruction that suspends execution in a lower power > state until the TSC (Time Stamp Counter) exceeds a certain value. > > Update the udelay() function to use TPAUSE on systems where it > is available. Note that we hard code the deeper (C0.2) sleep > state because exit latency is small compared to the "microseconds" > that usleep() will delay. > > ChangeLog: > - Change from v1 to v2: > 1. The patchset applies after Thomas's cleanup patch as below: > https://lkml.org/lkml/diff/2020/3/18/893/1 lkml.org is horrible. Please use lore.kernel.org if at all. Also please just add the patch to the series when posting so that people don't have to go through loops and hoops to grab that dependency. Thanks, tglx