From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2992536AbXDDCzn (ORCPT ); Tue, 3 Apr 2007 22:55:43 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S2992532AbXDDCzm (ORCPT ); Tue, 3 Apr 2007 22:55:42 -0400 Received: from netops-testserver-3-out.sgi.com ([192.48.171.28]:47410 "EHLO relay.sgi.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S2992536AbXDDCzl (ORCPT ); Tue, 3 Apr 2007 22:55:41 -0400 Date: Tue, 3 Apr 2007 19:55:38 -0700 From: Paul Jackson To: Andrew Morton Cc: drepper@redhat.com, linux-kernel@vger.kernel.org, ego@in.ibm.com, dipankar@in.ibm.com, mingo@elte.hu, oleg@tv-sign.ru Subject: Re: getting processor numbers Message-Id: <20070403195538.c3419684.pj@sgi.com> In-Reply-To: <20070403162349.583adf84.akpm@linux-foundation.org> References: <461286D6.2040407@redhat.com> <20070403131623.c6831607.akpm@linux-foundation.org> <4612BB89.8040102@redhat.com> <20070403141348.9bcdb13e.akpm@linux-foundation.org> <4612D175.30604@redhat.com> <20070403154831.37bde672.akpm@linux-foundation.org> <4612DCA2.2090400@redhat.com> <20070403162349.583adf84.akpm@linux-foundation.org> Organization: SGI X-Mailer: Sylpheed version 2.2.4 (GTK+ 2.8.3; i686-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Andrew wrote: > > But all this of course does not solve the issue sysconf() has. In > > sysconf we cannot use sched_getaffinity since all the systems CPUs must > > be reported. > > OK. > > This is excecptionally gruesome, but one could run sched_getaffinity() > against pid 1 (init). Which will break nicely in the OS-virtualised future > when the system has multiple pid-1-inits running in containers... That nicely breaks on typical cpuset managed systems as well, which frequently put init into a small cpuset (with the classic Unix daemon and login load), leaving the bulk of the system to be managed by a batch scheduler. -- I won't rest till it's the best ... Programmer, Linux Scalability Paul Jackson 1.925.600.0401