Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S261952AbVDCXIv (ORCPT ); Sun, 3 Apr 2005 19:08:51 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S261953AbVDCXIv (ORCPT ); Sun, 3 Apr 2005 19:08:51 -0400 Received: from ms-smtp-03.nyroc.rr.com ([24.24.2.57]:41350 "EHLO ms-smtp-03.nyroc.rr.com") by vger.kernel.org with ESMTP id S261952AbVDCXIn (ORCPT ); Sun, 3 Apr 2005 19:08:43 -0400 Subject: Re: sched /HT processor From: Steven Rostedt To: Arun Srinivas Cc: juhl-lkml@dif.dk, LKML In-Reply-To: References: Content-Type: text/plain Organization: Kihon Technologies Date: Sun, 03 Apr 2005 19:08:06 -0400 Message-Id: <1112569686.27149.138.camel@localhost.localdomain> Mime-Version: 1.0 X-Mailer: Evolution 2.0.4 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1328 Lines: 31 On Mon, 2005-04-04 at 04:22 +0530, Arun Srinivas wrote: > Thanks. yes, a reschedule may not take place after a ms, if the currently > running task cannot be preempted by another task. > > (1) But, can a reschedule happen within a millisec (or once a process is > scheduled can schedule() be called before the next millisec.) ? > Yes. For example: a high priority task may be waiting for some IO to come in. Right after the normal timer interrupt scheduled another task, the IO may come in and wake the high priority process up. This process will preempt the other task right away. (ie. less than 1 ms). > 2) Also in case argument (1) is not true, and I want rescheduling to be done > (i.e., schedule() called) in less than 1 ms , can I directly change the HZ > value in and recompile my kernel so that my timer > interrupt will occur frequently? > Well, 1) is true, but you can also increase HZ over 1000 if you like, but that will usually cause more overhead, since, although a schedule may not take place every HZ, a timer interrupt will. -- Steve - 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/