Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758172AbZJLVGF (ORCPT ); Mon, 12 Oct 2009 17:06:05 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1758154AbZJLVGE (ORCPT ); Mon, 12 Oct 2009 17:06:04 -0400 Received: from ey-out-2122.google.com ([74.125.78.26]:30903 "EHLO ey-out-2122.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757598AbZJLVGC (ORCPT ); Mon, 12 Oct 2009 17:06:02 -0400 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :cc:content-type; b=dfrJ/Gfy03WnmmKS+7FYLLtSZ3hHjkmxY5udDALKxdlPRH9+NkPkpuZPDLhrKtuAA4 3Ioi+8kUVztZodVawMWf/too7FlcQNEFDPSj7XqkAfOfmnNzGcLyJtOiHCBbIeTVq9gX iSgL7+amButv4FIK6u858knDwUMUpKGcfU1nk= MIME-Version: 1.0 In-Reply-To: References: <2d05c4580910121100v702cbdddua9bd8de971fecaa2@mail.gmail.com> Date: Mon, 12 Oct 2009 23:04:55 +0200 Message-ID: <2d05c4580910121404x7d09ea3dvde1aa49b05d2e3fc@mail.gmail.com> Subject: Re: Real time kernel From: Dragoslav Zaric To: Christoph Lameter Cc: LKML Content-Type: text/plain; charset=ISO-8859-1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1362 Lines: 29 This is definition from http://rt.wiki.kernel.org/ ------------------------------------------------------------------------- Real-time applications have operational deadlines between some triggering event and the application's response to that event. To meet these operational deadlines, programmers use real-time operating systems (RTOS) on which the maximum response time can be calculated or measured reliably for the given application and environment. ------------------------------------------------------------------------- So for specific requirements I would not say, you get slower kernel, you get purpose-making kernel, because on these kind of systems you probably do not do anything. It is probably the system that listens and responds to some events. Do you want to say, when using preemption in "normal user mode", Linux works slower then without preemption ? It makes sense, "because the latency of a task only depends on the tasks running at equal or higher priorities, all other tasks can be ignored." (http://rt.wiki.kernel.org/index.php/Frequently_Asked_Questions#What_is_real-time.3F) Thanks -- 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/