From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Fri, 21 Sep 2001 04:48:27 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Fri, 21 Sep 2001 04:48:17 -0400 Received: from gw.framfab.dk ([194.239.251.2]:2591 "HELO [194.239.251.2]") by vger.kernel.org with SMTP id ; Fri, 21 Sep 2001 04:48:08 -0400 Message-ID: <3BAAFECC.9060701@fugmann.dhs.org> Date: Fri, 21 Sep 2001 10:48:12 +0200 From: Anders Peter Fugmann User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:0.9.4) Gecko/20010913 X-Accept-Language: en-us MIME-Version: 1.0 To: Samuel T Ting Cc: linux-kernel@vger.kernel.org Subject: Re: Preemptive kernel and vm management in 2.4.9 In-Reply-To: Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org The preemption patch helps on problems with high letencies. High latencies means that the kernel is busy doing something, so that other threads will get starved. This problem is especially seen when using multimedia. The most discussed problem is listening to a MP3-file, while the machine has a high load. What we want to avoid is skips in the music. Tee preemption patch helps, because it allows preemption of processes running in kernel space, meaning that the sheduler can choose another process, even though the process running is in kernel-space. (A very crude description, I know, but AFAIK is is the general idea) Without the preemption patch, whenever a userprocess makes a call to the kernel, it could not be resheduled before the call had returned. This results in very high latencies for some kernel calls. Hope it helps, othervice please refere to documentation and recent lkml-threads. Anders Fugmann Samuel T Ting wrote: > Hello all, > > Lately, I have been hearing a lot about preemptive kernels on the list. > I have just started looking into kernel internals, so could somebody > explain what kernel preemption is? > > Also, how does virtual memory management in 2.4.9 work? > > Thanks! > > Samuel Ting > > - > 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/ > >