Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Mon, 16 Jul 2001 14:26:51 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Mon, 16 Jul 2001 14:26:41 -0400 Received: from e1.ny.us.ibm.com ([32.97.182.101]:30135 "EHLO e1.ny.us.ibm.com") by vger.kernel.org with ESMTP id ; Mon, 16 Jul 2001 14:26:23 -0400 Importance: Normal Subject: Re: CPU affinity & IPI latency To: lse-tech@lists.sourceforge.net Cc: linux-kernel@vger.kernel.org X-Mailer: Lotus Notes Release 5.0.5 September 22, 2000 Message-ID: From: "Hubertus Franke" Date: Mon, 16 Jul 2001 14:26:23 -0400 X-MIMETrack: Serialize by Router on D01ML244/01/M/IBM(Release 5.0.8 |June 18, 2001) at 07/16/2001 02:26:10 PM MIME-Version: 1.0 Content-type: text/plain; charset=us-ascii Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Well, actually the sole purpose of is to lock a task out of a scheduling decision. Remember during transient states, there are two tasks that have the flag set for a particular cpu. So I think using is kosher and preferred in this situation, IMHO. As you saw from David Levines reply, he thinks that a list is more appropriate for more generic decision support. But I don't like the fact that you lock down several tasks at that point. In my solution, you return the task back to general schedulability. Hubertus Franke Enterprise Linux Group (Mgr), Linux Technology Center (Member Scalability) email: frankeh@us.ibm.com Mike Kravetz on 07/16/2001 12:14:46 PM To: Hubertus Franke/Watson/IBM@IBMUS cc: Mike Kravetz , lse-tech@lists.sourceforge.net, linux-kernel@vger.kernel.org Subject: Re: CPU affinity & IPI latency On Fri, Jul 13, 2001 at 11:25:21PM -0400, Hubertus Franke wrote: > > Mike, could we utilize the existing mechanism such as has_cpu. > I like it. Especially the way you eliminated the situation where we would have multiple tasks waiting for schedule. Hope this is not a frequent situation!!! The only thing I don't like is the use of has_cpu to prevent the task from being scheduled. Right now, I can't think of any problems with it. However, in the past I have been bit by using fields for purposes other than what they were designed for. -- Mike Kravetz mkravetz@sequent.com IBM Linux Technology Center - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/