Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1161198AbWASK06 (ORCPT ); Thu, 19 Jan 2006 05:26:58 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1161337AbWASK06 (ORCPT ); Thu, 19 Jan 2006 05:26:58 -0500 Received: from general.keba.co.at ([193.154.24.243]:19332 "EHLO helga.keba.co.at") by vger.kernel.org with ESMTP id S1161198AbWASK05 convert rfc822-to-8bit (ORCPT ); Thu, 19 Jan 2006 05:26:57 -0500 X-MimeOLE: Produced By Microsoft Exchange V6.5.7226.0 Content-class: urn:content-classes:message MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 8BIT Subject: RE: My vote against eepro* removal Date: Thu, 19 Jan 2006 11:26:51 +0100 Message-ID: X-MS-Has-Attach: X-MS-TNEF-Correlator: Thread-Topic: My vote against eepro* removal Thread-Index: AcYcyXLu7ygelEPvQ1GAEXvAEf8NMQAFtQ5Q From: "kus Kusche Klaus" To: "Lee Revell" Cc: Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2424 Lines: 56 > From: Lee Revell > On Thu, 2006-01-19 at 08:19 +0100, kus Kusche Klaus wrote: > > Last time I tested (around 2.6.12), eepro100 worked much better > > in -rt kernels w.r.t. latencies than e100: > > > > e100 caused a periodic latency of about 500 microseconds > > exactly every 2 seconds, no matter what the load on the interface > > was (i.e. even on an idle interface). > > > > eepro100 did not show any latencies that long, it worked much > > smoother w.r.t. latencies. > > > > Of course I would prefer to have e100 fixed over keeping eepro100 > > around forever, but the last time I checked, it still wasn't fixed. > > Please provide latency traces to illustrate the problematic code path. It's not a "latency": As far as I can tell, interrupts or preemption are not disabled, the latency tracer doesn't show anything. I just noticed that low-pri rt processes did not get scheduled for about 500 microseconds when e100 was active (even if the net was idle), and that there were no such breaks with eepro100. I didn't analyze it in detail at that time, I believed that the e100 interrupt handler thread was running every 2 seconds for 500 microseconds, because the interrupt count of eth0 incremented every 2 seconds, exactly when my rt processes paused. This would be bad: That irq thread is at rt prio 47 on my system, above many importent things. However, I checked more closely now, and found out that only a small portion of the 500 microseconds is spent in the irq thread. Most of it is spent in the timer thread, at rt prio 1, so the whole thing is a much smaller problem than I originally believed. Must be the function e100_watchdog. > It sounds like you have known about this issue for a while, were you > waiting for it to fix itself? See my other reply: I didn't notice that eepro100 is to be removed, and as long as eepro100 was there, it was no problem for me. -- Klaus Kusche (Software Development - Control Systems) KEBA AG Gewerbepark Urfahr, A-4041 Linz, Austria (Europe) Tel: +43 / 732 / 7090-3120 Fax: +43 / 732 / 7090-6301 E-Mail: kus@keba.com WWW: www.keba.com - 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/