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=-1.0 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, 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 4BB5DC5B578 for ; Thu, 4 Jul 2019 00:37:59 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 1EFE5218B8 for ; Thu, 4 Jul 2019 00:37:59 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="jjed64kf" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727309AbfGDAh5 (ORCPT ); Wed, 3 Jul 2019 20:37:57 -0400 Received: from mail-ot1-f68.google.com ([209.85.210.68]:40445 "EHLO mail-ot1-f68.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727264AbfGDAhw (ORCPT ); Wed, 3 Jul 2019 20:37:52 -0400 Received: by mail-ot1-f68.google.com with SMTP id e8so4296136otl.7; Wed, 03 Jul 2019 17:37:52 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=kxKadiwStil9way1kU8jzMyzFN0LuSwbCGE20CmySOI=; b=jjed64kf8UigzT5xPFuCz/Amv7WWAE+6rjJhQtW2VDYH4cmOmzA1vr44kYsoBJTpaz dJmiqSYb2ZTRxwDk5JuHdcjKJ1tt72V4tLsn/8xmWsM/qHhCw/Cr1Qs+zLIW2q8s5iuC MQSfIJ+VsVcLXWy+RUH9ED/MSwMEMEBjK/KP6ffPBTB6e6uWXWZI1ifhvzW58Qyx7Vvr ZN22H0p7boLb9J44FTlPFArT0f5wu4yteSCNHHpkeNr7RTHwux9vATkCmlo8CEGbSew4 kx97el09vrfVjyi0FZbZgiXfUR+fVhTswAljsD+iQn2erhsvaOybMBJU1fF8SS6VWd8c arOg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=kxKadiwStil9way1kU8jzMyzFN0LuSwbCGE20CmySOI=; b=GZNbAhG8AcZHCLBvgKQYZPJTL++tg0X+IJIBWg3JPvxf6pRS0J5DkaFxt1RJdWAcv6 UINOVLTMl0NrN3dtjKglmu56T1jV5gd8KLdFIKbBJ8d6hmc5mvep9tqS20oWznIWbWQT y3LAa5GNeTiP76NcRYmBI3GNLgF7IpVciMp91Qxy2D+FWixTupvVGZTJxyhwzlnhFJ4/ 1sA/8MEvEhDqDgF1i26BQh70rbt4wOxk2EWkSgcj6OsTjKFN7ncFKZQUeVwbx+EKx5UP u5UaxhjcG6aC0vzR6bhNBbhGzMKGW2GuPX+gaDb2ZSQCGIHDih5whw0qau5UbKYo+7MJ a4Ww== X-Gm-Message-State: APjAAAWJSl1JNPLnJs4jTfBYbLh3WkFAN8CJsixLDzAPJMalVETjrhs3 gpCQwV61xjAp0c26Iwy9z+oY1GDaslJvqIUL1YQ= X-Google-Smtp-Source: APXvYqzeYi0PDoaiISTn2M9/7d/KVcBfQ7O2/IKHGPqh7tH9DMLVPheOsLoY4L/bml6SlwrjRhF2NNyFcfJgV6g/VzA= X-Received: by 2002:a9d:6959:: with SMTP id p25mr12145726oto.118.1562200672188; Wed, 03 Jul 2019 17:37:52 -0700 (PDT) MIME-Version: 1.0 References: <1560474949-20497-1-git-send-email-wanpengli@tencent.com> <1560474949-20497-2-git-send-email-wanpengli@tencent.com> <18fd2372-45d8-0bff-79e7-373a8b7d129c@redhat.com> In-Reply-To: <18fd2372-45d8-0bff-79e7-373a8b7d129c@redhat.com> From: Wanpeng Li Date: Thu, 4 Jul 2019 08:37:44 +0800 Message-ID: Subject: Re: [PATCH v4 1/2] KVM: LAPIC: Optimize timer latency consider world switch time To: Paolo Bonzini Cc: LKML , kvm , =?UTF-8?B?UmFkaW0gS3LEjW3DocWZ?= Content-Type: text/plain; charset="UTF-8" Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org On Wed, 3 Jul 2019 at 22:13, Paolo Bonzini wrote: > > On 03/07/19 02:48, Wanpeng Li wrote: > > Hi Paolo, how about this patchset? Patch 2/2 is easy to take, do you > > have more concern about patch 1/2? > > I don't know. It seems somewhat hard to tune and in cyclictest it only > happens for preemption_timer=N. Are you using preemption_timer=N > together with the LAPIC-timer-on-service-CPU patches? A 25ns conservative value makes no benefit for cyclictest any more even when preemption_timer=N. Btw, maybe it is the time to merge the LAPIC-timer-on-service-CPU patches now. :) Regards, Wanpeng Li