From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Sat, 22 Sep 2001 17:33:10 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Sat, 22 Sep 2001 17:33:00 -0400 Received: from [195.223.140.107] ([195.223.140.107]:7671 "EHLO athlon.random") by vger.kernel.org with ESMTP id ; Sat, 22 Sep 2001 17:32:54 -0400 Date: Sat, 22 Sep 2001 23:33:10 +0200 From: Andrea Arcangeli To: Roger Larsson Cc: Robert Love , Andre Pang , linux-kernel@vger.kernel.org, safemode@speakeasy.net, Dieter.Nuetzel@hamburg.de, iafilius@xs4all.nl, ilsensine@inwind.it, george@mvista.com Subject: Re: ksoftirqd? (Was: Re: [PATCH] Preemption Latency Measurement Tool) Message-ID: <20010922233310.A1788@athlon.random> In-Reply-To: <1000939458.3853.17.camel@phantasy> <200109221301.f8MD1n129687@mailc.telia.com> <20010922151453.B976@athlon.random> <200109222056.f8MKu8K24322@maile.telia.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <200109222056.f8MKu8K24322@maile.telia.com>; from roger.larsson@norran.net on Sat, Sep 22, 2001 at 10:51:16PM +0200 X-GnuPG-Key-URL: http://e-mind.com/~andrea/aa.gnupg.asc X-PGP-Key-URL: http://e-mind.com/~andrea/aa.asc Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Sat, Sep 22, 2001 at 10:51:16PM +0200, Roger Larsson wrote: > On Saturday 22 September 2001 15.14, Andrea Arcangeli wrote: > > On Sat, Sep 22, 2001 at 02:56:58PM +0200, Roger Larsson wrote: > > > Hi, > > > > > > We have a new kid on the block since we started thinking of a preemptive > > > kernel. > > > > > > ksoftirqd... > > > > > > Running with nice 19 (shouldn't it really be -19?) > > I repeat this question - should it be nice 19 and not nice -19 (not nice)? Being it +19 it is light with respect to the other tasks in the system, mainly considering there's one for each cpu. > Sep 22 22:37:38 jeloin logger: *** ./stress_dbench begin *** > Sep 22 22:37:42 jeloin kernel: ksoftirqd: do_softirq > Sep 22 22:37:44 jeloin last message repeated 2 times > Sep 22 22:37:48 jeloin kernel: Latency 8ms PID 7 %% kupdated > Sep 22 22:37:49 jeloin kernel: ksoftirqd: do_softirq > Sep 22 22:38:19 jeloin last message repeated 18 times > Sep 22 22:38:20 jeloin su: (to root) roger on /dev/pts/2 > Sep 22 22:38:20 jeloin PAM-unix2[988]: session started for user root, service > su > Sep 22 22:38:23 jeloin kernel: ksoftirqd: do_softirq > Sep 22 22:38:24 jeloin modprobe: modprobe: Can't locate module net-pf-10 > Sep 22 22:38:24 jeloin kernel: ksoftirqd: do_softirq > Sep 22 22:38:58 jeloin last message repeated 20 times > Sep 22 22:39:05 jeloin last message repeated 4 times > Sep 22 22:42:03 jeloin kernel: ksoftirqd: do_softirq > Sep 22 22:43:58 jeloin logger: *** ./stress_dbench end *** one reschedule every few seconds sounds ok. > Possibly but the other case is quite common too... if you try to put a printk also in do_softirq you'll see why it is not the common case :) also you may want to put the printk in the schedule() path, ksoftirqd may just be rescheduled once, and run many of the do_softirq(). Andrea