From mboxrd@z Thu Jan 1 00:00:00 1970 From: Robert Schwebel Subject: Re: jitter bursts Date: Sat, 1 Sep 2007 11:15:30 +0200 Message-ID: <20070901091530.GW23573@pengutronix.de> References: <20070831151727.GT23573@pengutronix.de> <34ac6d890708310855v413383cm2bd725501a685842@mail.gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=iso-8859-15 Cc: linux-rt-users@vger.kernel.org, Michael Olbrich , kiszka@rts.uni-hannover.de To: Girish kathalagiri Return-path: Received: from metis.extern.pengutronix.de ([83.236.181.26]:59304 "EHLO metis.extern.pengutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752738AbXIAJPg (ORCPT ); Sat, 1 Sep 2007 05:15:36 -0400 Content-Disposition: inline In-Reply-To: <34ac6d890708310855v413383cm2bd725501a685842@mail.gmail.com> Sender: linux-rt-users-owner@vger.kernel.org List-Id: linux-rt-users.vger.kernel.org On Fri, Aug 31, 2007 at 09:25:08PM +0530, Girish kathalagiri wrote: > We also had similar problems when where we face these kind of periodic > jitter. In our case we used Intel 82551ER Fast Ethernet Controller( > e100 driver). The problem with ours was the with the microcode (in > e100.c) of the adapter which had default algorithm where the hardware > was holding of the interrupts until X packets or Y usecs have expired. > > This generated a periodic jitter that was 400-500 us more than the usual one. > This was solved by making the hardware generate interrupt on every frame. > In e100.c this can be done by changing the values of INTDELAY, > BUNDDLEMAX and BUNDDLESMALL (CPU saver parameters) Sounds good, we'll try that on monday. Although both boxes have e100 network cards, I think Michael has also tested with two other cards. But we'll recheck. Robert -- Pengutronix - Linux Solutions for Science and Industry Entwicklungszentrum Nord http://www.pengutronix.de