From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Tue, 30 Jul 2002 14:31:14 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Tue, 30 Jul 2002 14:31:13 -0400 Received: from gatekeeper.agave.com ([209.241.135.2]:30112 "EHLO agave.com") by vger.kernel.org with ESMTP id ; Tue, 30 Jul 2002 14:31:10 -0400 Message-ID: <3D46DC36.4469328E@caseta.com> Date: Tue, 30 Jul 2002 13:34:30 -0500 From: Jim Duchek Organization: Caseta Technologies X-Mailer: Mozilla 4.76 [en] (X11; U; Linux 2.2.18pre21 i686) X-Accept-Language: en MIME-Version: 1.0 To: linux-kernel@vger.kernel.org Subject: Quick Q on kernel threads and RT thread priorities Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Hello. I'm using kernel 2.4.18 in a semi-RT application. I'm using the SCHED_RR scheduler with a number of processes, priorities running from 5 up through 90. Default processes, of course, run under SCHED_OTHER at priority 0. There are a number of kernel threads running, quick example from busybox's ps (modified to show scheduling prios), see bottom of email. I have tested and the priorities do work correctly -- a prio 50 process can completely starve a prio 49 process, as it should be. My question is: Do I need to worry about kernel processes, such as [keventd], [eth0], etc, running at 0 priority? Should I run them at 99? I have experienced no problems seeing ethernet traffic with process 53 in the list below at prio 0 and a CPU-starving test process running at prio 50. I am worried that the kernel may lock up if it's processes get starved. I am also worried that some of these processes may depend on the fact that everyone can get equal scheduling and setting them to 99 will starve my application. Any advice? Thanks in advance, Jim Duchek Caseta Technologies, inc. sample PS output: PID Uid Pri VmSize Stat Command 1 root 0 1724 S init 2 root 0 S [keventd] 3 root 0 S [ksoftirqd_CPU0] 4 root 0 S [kswapd] 5 root 0 S [bdflush] 6 root 0 S [kupdated] 7 root 0 S [mtdblockd] 20 root 0 1700 S syslogd -m 0 22 root 0 1708 S klogd 53 root 0 S [eth0] 63 root 50 1676 S /usr/sbin/inetd /etc/inetd.conf 64 root 0 1724 S init 65 root 0 1728 S init 66 root 50 2112 S telnetd 67 root 50 1784 S -sh 142 root 50 2112 R telnetd 143 root 50 1784 S -sh 871 root 50 1844 R ps