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=-4.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,SIGNED_OFF_BY,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 ECC84C3A5A6 for ; Wed, 28 Aug 2019 23:37:49 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id C4EBF233FF for ; Wed, 28 Aug 2019 23:37:49 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1567035469; bh=EhEjFW+KsaoKMHjqDkQxAsY+zVP9owpde5YL942AqFQ=; h=References:In-Reply-To:From:Date:Subject:To:Cc:List-ID:From; b=N4FI9KlybkBbPb1H62qkzWOe+hRiQIArkNxTQpE54lDDXluqAsuT+PF32K7Rzn6is 1FKOdQOm91BUEDMBtnHKSL8OFyKzv9evrEbNU7gwhEBCg7iT51i6sgzqV6gg5XQEC8 8TkcXlI0L5kkTyL3+N0MiIUB71X9WrwbEDFcr3oU= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727086AbfH1Xht convert rfc822-to-8bit (ORCPT ); Wed, 28 Aug 2019 19:37:49 -0400 Received: from mail-ot1-f68.google.com ([209.85.210.68]:42044 "EHLO mail-ot1-f68.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726935AbfH1Xhs (ORCPT ); Wed, 28 Aug 2019 19:37:48 -0400 Received: by mail-ot1-f68.google.com with SMTP id j7so1575123ota.9; Wed, 28 Aug 2019 16:37:48 -0700 (PDT) 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:content-transfer-encoding; bh=0WiNNlZ19WAx+O8CTTiGYwNeR0ZDw2Ysbv/e1WoYV9o=; b=NzkWW2rEUGn2hm/+Q47nfXQgS+iditfvHFjoCGWPnNViisDyUh6UvUmPOb65gsI/lF zuaC7Xxrb5ctQXyRUOOyy/h1IwuZvE+zN4e3+oNsKirgxmXjvDpQQXuozaSvDkdVg9Cp yqPjw/dg3dbI5/Ygmw+SLiOVx47+r9hQ2+sKrFCE54kekC0uAUDSjJmNq6a5x6LsTtsu t12qTTd4XdWTL3BcYPeHfY0uNf3s5O6GBh3ASBHgNsaucY/E2wgXzYBjfv4zt9AfAxZN 4SVn5aoXJzcyXIZnLGEEcgVqdSk4nwYWL5ekaqJR/FcezLmm0qPxIUvNLOvGGgnXydFk 38Lw== X-Gm-Message-State: APjAAAXVjpTOUYRSE1sEn6DzPM323ZmQx3fqTW7nN/MexHDcm2EkcxuP D9oo/0mzQclC1WrxeqBTfNX2zuOryNHIvMGHkkM= X-Google-Smtp-Source: APXvYqxk5XxurJ7D0mvitMxzIf9FQRgo2vpruN5+wj43N/LYuGLxqqtW3SsJxC+VaDntTllf2UOHc/U87dV9dPOR7W8= X-Received: by 2002:a9d:12d1:: with SMTP id g75mr5311313otg.189.1567035467967; Wed, 28 Aug 2019 16:37:47 -0700 (PDT) MIME-Version: 1.0 References: <1564643196-7797-1-git-send-email-wanpengli@tencent.com> <7b1e3025-f513-7068-32ac-4830d67b65ac@intel.com> <20190803202058.GA9316@amt.cnet> <20190826204045.GA24697@amt.cnet> <20190828143916.GA13725@amt.cnet> In-Reply-To: <20190828143916.GA13725@amt.cnet> From: "Rafael J. Wysocki" Date: Thu, 29 Aug 2019 01:37:35 +0200 Message-ID: Subject: Re: [PATCH] cpuidle-haltpoll: Enable kvm guest polling when dedicated physical CPUs are available To: Marcelo Tosatti Cc: "Rafael J. Wysocki" , Wanpeng Li , Paolo Bonzini , "Rafael J. Wysocki" , LKML , kvm , =?UTF-8?B?UmFkaW0gS3LEjW3DocWZ?= , Linux PM , "Michael S. Tsirkin" Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Aug 28, 2019 at 4:39 PM Marcelo Tosatti wrote: > > On Wed, Aug 28, 2019 at 10:45:44AM +0200, Rafael J. Wysocki wrote: > > On Wed, Aug 28, 2019 at 10:34 AM Wanpeng Li wrote: > > > > > > On Tue, 27 Aug 2019 at 08:43, Wanpeng Li wrote: > > > > > > > > Cc Michael S. Tsirkin, > > > > On Tue, 27 Aug 2019 at 04:42, Marcelo Tosatti wrote: > > > > > > > > > > On Tue, Aug 13, 2019 at 08:55:29AM +0800, Wanpeng Li wrote: > > > > > > On Sun, 4 Aug 2019 at 04:21, Marcelo Tosatti wrote: > > > > > > > > > > > > > > On Thu, Aug 01, 2019 at 06:54:49PM +0200, Paolo Bonzini wrote: > > > > > > > > On 01/08/19 18:51, Rafael J. Wysocki wrote: > > > > > > > > > On 8/1/2019 9:06 AM, Wanpeng Li wrote: > > > > > > > > >> From: Wanpeng Li > > > > > > > > >> > > > > > > > > >> The downside of guest side polling is that polling is performed even > > > > > > > > >> with other runnable tasks in the host. However, even if poll in kvm > > > > > > > > >> can aware whether or not other runnable tasks in the same pCPU, it > > > > > > > > >> can still incur extra overhead in over-subscribe scenario. Now we can > > > > > > > > >> just enable guest polling when dedicated pCPUs are available. > > > > > > > > >> > > > > > > > > >> Cc: Rafael J. Wysocki > > > > > > > > >> Cc: Paolo Bonzini > > > > > > > > >> Cc: Radim Krčmář > > > > > > > > >> Cc: Marcelo Tosatti > > > > > > > > >> Signed-off-by: Wanpeng Li > > > > > > > > > > > > > > > > > > Paolo, Marcelo, any comments? > > > > > > > > > > > > > > > > Yes, it's a good idea. > > > > > > > > > > > > > > > > Acked-by: Paolo Bonzini > > > > > > Hi Marcelo, > > > > > > If you don't have more concern, I guess Rafael can apply this patch > > > now since the merge window is not too far. > > > > I will likely queue it up later today and it will go to linux-next > > early next week. > > > > Thanks! > > NACK patch. I got an ACK from Paolo on it, though. Convince Paolo to withdraw his ACK if you want it to not be applied. > Just don't load the haltpoll driver. And why would that be better?