From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751549AbbJKH0y (ORCPT ); Sun, 11 Oct 2015 03:26:54 -0400 Received: from smtp1.it.da.ut.ee ([193.40.5.66]:53122 "EHLO smtp1.it.da.ut.ee" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751418AbbJKH0X (ORCPT ); Sun, 11 Oct 2015 03:26:23 -0400 Date: Sun, 11 Oct 2015 10:27:54 +0300 (EEST) From: Meelis Roos To: "Paul E. McKenney" cc: Linux Kernel list , Thomas Gleixner , Frederic Weisbecker Subject: Re: 4.2: CONFIG_NO_HZ_FULL_ALL effectively disabling non-boot CPUs In-Reply-To: <20151010192439.GY3910@linux.vnet.ibm.com> Message-ID: References: <20151010192439.GY3910@linux.vnet.ibm.com> User-Agent: Alpine 2.20 (LRH 67 2015-01-07) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org > > Short summary: turning on CONFIG_NO_HZ_FULL_ALL seems to disable all > > non-boot CPUs for scheduler. [...] > This is expected and intended behavior. The whole point of > CONFIG_NO_HZ_FULL_ALL is to keep everything off of the non-boot CPUs > that is not explicitly placed there. Without CONFIG_NO_HZ_FULL_ALL, > you can use the nohz_full boot parameter to select exactly which > CPUs are to behave this way. OK, thanks - disabled it on my desktops anyway now. Perhaps the Kconfig description of it should explian the consequences more clearly so other people do not stumble upon it like I did? -- Meelis Roos (mroos@linux.ee)