Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Sat, 28 Apr 2001 07:52:34 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Sat, 28 Apr 2001 07:52:24 -0400 Received: from fep01.swip.net ([130.244.199.129]:64487 "EHLO fep01-svc.swip.net") by vger.kernel.org with ESMTP id ; Sat, 28 Apr 2001 07:52:12 -0400 Date: Sat, 28 Apr 2001 13:52:06 +0200 (CEST) From: Peter Osterlund X-X-Sender: To: Linus Torvalds cc: Subject: 2.4.4 sluggish under fork load Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=ISO-8859-1 Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org I have noticed that 2.4.4 feels a lot less responsive than 2.4.3 under fork load. This is caused by the "run child first after fork" patch. I have tested on two different UP x86 systems running redhat 7.0. For example, when running the gcc configure script, the X mouse pointer is very jerky. The configure script itself runs approximately as fast as in 2.4.3. Another thing is that the bash loop "while true ; do /bin/true ; done" is not possible to interrupt with ctrl-c. A third thing I noticed is that starting a gnome session in redhat 7.0 takes longer. (It takes more time for the gnome splash screen to appear.) Reverting the fork patch makes all these problems go away on my machine. I'm not saying that this is necessarily a good idea, that patch might be good for other reasons. --- linux-2.4.4/kernel/fork.c~ Sat Apr 28 09:46:58 2001 +++ linux-2.4.4/kernel/fork.c Sat Apr 28 11:14:33 2001 @@ -674,9 +674,16 @@ * and then exec(). This is only important in the first timeslice. * In the long run, the scheduling behavior is unchanged. */ +#if 0 p->counter = current->counter; current->counter = 0; current->need_resched = 1; +#else + p->counter = (current->counter + 1) >> 1; + current->counter >>= 1; + if (!current->counter) + current->need_resched = 1; +#endif /* * Ok, add it to the run-queues and make it -- Peter ?sterlund peter.osterlund@mailbox.swipnet.se Sk?ndalsv?gen 35 http://home1.swipnet.se/~w-15919 S-128 66 Sk?ndal +46 8 942647 Sweden - 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/