Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S262652AbVDAJI6 (ORCPT ); Fri, 1 Apr 2005 04:08:58 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S261605AbVDAJI6 (ORCPT ); Fri, 1 Apr 2005 04:08:58 -0500 Received: from general.keba.co.at ([193.154.24.243]:35923 "EHLO helga.keba.co.at") by vger.kernel.org with ESMTP id S262652AbVDAJIL convert rfc822-to-8bit (ORCPT ); Fri, 1 Apr 2005 04:08:11 -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: 2.6.11, IDE: Strange scheduling behaviour: high-pri RT process not scheduled? Date: Fri, 1 Apr 2005 11:07:54 +0200 Message-ID: X-MS-Has-Attach: X-MS-TNEF-Correlator: Thread-Topic: 2.6.11, IDE: Strange scheduling behaviour: high-pri RT process not scheduled? Thread-Index: AcU2BZvvgd/4rBgGTNqQgCCbxR4G+wAk5B/w From: "kus Kusche Klaus" To: "Ingo Molnar" , "kus Kusche Klaus" Cc: , , , "Florian Schmidt" , "Alan Stern" Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1446 Lines: 42 > > The following tests are made with 'IRQ 8' at 95, rtc_wakeup > at 89(99): > > * Heavy mmap load, no oom: max jitter: 42.1% ( 51 usec) > > * Heavy mmap load, oom: max jitter: 11989.2% (14635 usec) > > (but still "missed irqs: 0", so IRQ 8 was also blocked for 14 ms) > > did you get any kernel messages in that time? (about missed > irqs, etc.) > Please do a 'dmesg -n 0' to minimize the effect of kernel messages. Excellent, thanks! It turned out that the latencies are not caused by the kernel messages themselves, but by sending them to a serial console (which was off), in all my high latency cases at rtpri 89(99). After removing the serial console from the boot parameters, * the OOM timings are back to normal (around 50 microseconds) * the USB error and remove timings are back to normal * the USB plugin timings are in the range of the USB read (which is up to 1 ms - still bad) However, latencies at rtprio 2 are still very frustrating (details will follow). -- Klaus Kusche Entwicklung Software - Steuerung Software Development - Control KEBA AG A-4041 Linz Gewerbepark Urfahr Tel +43 / 732 / 7090-3120 Fax +43 / 732 / 7090-8919 E-Mail: kus@keba.com 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/