From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from systemhalted (CPE0080c82c70ca.cpe.net.cable.rogers.com [24.112.224.149]) by dsl2.external.hp.com (Postfix) with ESMTP id 618B14829 for ; Tue, 8 Oct 2002 17:58:29 -0600 (MDT) Date: Tue, 8 Oct 2002 19:48:54 -0400 From: Carlos O'Donell To: John Marvin Cc: parisc-linux@lists.parisc-linux.org Subject: Re: [parisc-linux] ksoftirqd eats 100% cpu :-( Message-ID: <20021008234854.GE18202@systemhalted> References: <200210081427.IAA27522@udlkern.fc.hp.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii In-Reply-To: <200210081427.IAA27522@udlkern.fc.hp.com> Sender: parisc-linux-admin@lists.parisc-linux.org Errors-To: parisc-linux-admin@lists.parisc-linux.org List-Help: List-Post: List-Subscribe: , List-Id: parisc-linux developers list List-Unsubscribe: , List-Archive: > > > It's a bug/feature related to the HIL drivers. > > Since we have to poll the HIL ports the whole time > > the bunch of running timers increase the ksoftirqd load a lot. > > I understand that polling is necessary while sending commands out > to hil devices, but input should be interrupt driven. What is the > reason for all of the polling? > > John Marvin > jsm@fc.hp.com It's interrupt driven, but the ISR _always_ calls tasklet_schedule to do the real work. The HIL state machine and SERIO layer hooks in a function to it's own tasklet so it can update on interrupt. Most drivers usage of tasklets involves: a- Setup and enable during module init b- Leave them alone. I assume that this is the case, because tasklets are CPU intensive. It would be nice to have someone investiage this... if not, it goes on the end of my now _really_ long todo list :) c.