From mboxrd@z Thu Jan 1 00:00:00 1970 From: Iratxo Pichel Ortiz Subject: NOHZ: local_softirq_pending Date: Sun, 14 Jun 2009 17:28:28 +0200 Message-ID: <4A35171C.9090800@albentia.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: QUOTED-PRINTABLE Cc: Iratxo Pichel Ortiz To: linux-rt-users@vger.kernel.org Return-path: Received: from llsc199-a04.servidoresdns.net ([82.223.190.46]:60596 "EHLO llsc199-a04.servidoresdns.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755540AbZFNPhI (ORCPT ); Sun, 14 Jun 2009 11:37:08 -0400 Sender: linux-rt-users-owner@vger.kernel.org List-ID: Hi there, I hope that someone in this list could help me trace down this issue I=20 am seeing. I am using 2.6.30-rt16 RT Kernel on a IXP425 system. The system is=20 running an experimental comm stack that has been working quite well wit= h=20 2.6.26-rt2 for a very long time (> 100days). When the system boots, every 180s aprox, I see this traces in the dmesg= : 42949422.930000] NOHZ: local_softirq_pending 02 [42949422.940000] NOHZ: local_softirq_pending 02 [42949422.950000] NOHZ: local_softirq_pending 02 [42949422.960000] ISR HIHG LATENCY 30073 [42949596.920000] NOHZ: local_softirq_pending 02 [42949596.930000] NOHZ: local_softirq_pending 02 [42949596.940000] NOHZ: local_softirq_pending 02 [42949596.950000] NOHZ: local_softirq_pending 02 [42949596.960000] ISR HIHG LATENCY 40066 The "ISR HIGH LATENCY" is small latency measurement that I have done in= =20 the ISR function of the driver. Hw is ticking the system every 2.5ms an= d=20 the usual run-time of the ISR handler is well under 200us. Every aprox=20 180seconds, suddenly this run-time get as high as 50ms. It is very highly probable that the problem is inside my driver, becaus= e=20 if I dont load the modules, this "NOHZ..." trace is not shown. Anyway, = I=20 would like to know if this "issue" is triggered by some known cause, or= =20 at least any idea where to start looking at. Please, CC me as I am not subscribed to the list. Thank you very much in advance and best regards! Iratxo. Another run: [ 96.950000] NOHZ: local_softirq_pending 02 [ 96.960000] NOHZ: local_softirq_pending 02 [ 96.970000] NOHZ: local_softirq_pending 02 [ 97.000000] ISR HIGH LATENCY 50068 [ 270.000000] ISR HIGH LATENCY 50048 [ 463.000000] ISR HIGH LATENCY 50049 [ 643.000000] ISR HIGH LATENCY 50047 --=20 Iratxo Pichel Ortiz Software Development Manager Albentia Systems S.A. http://www.albentia.com Tel: +34 914400567 Cel: +34 663808405 =46ax: +34 914400569 C\Margarita Salas 22 Parque Tecnol=F3gico de Legan=E9s Legan=E9s (28918) Madrid Spain -- To unsubscribe from this list: send the line "unsubscribe linux-rt-user= s" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html