Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932087AbZDWVip (ORCPT ); Thu, 23 Apr 2009 17:38:45 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754998AbZDWVif (ORCPT ); Thu, 23 Apr 2009 17:38:35 -0400 Received: from e38.co.us.ibm.com ([32.97.110.159]:45835 "EHLO e38.co.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753066AbZDWVid (ORCPT ); Thu, 23 Apr 2009 17:38:33 -0400 Message-ID: <49F0DFD7.5040107@linux.vnet.ibm.com> Date: Thu, 23 Apr 2009 14:38:31 -0700 From: jvrao User-Agent: Thunderbird 2.0.0.21 (Windows/20090302) MIME-Version: 1.0 To: Andrew Vasquez CC: LKML , rt-users , Mike Anderson , "Luis Claudio R. Goncalves" , Linux Driver Subject: Re: Interrupts are being dropped under heavy IO on -rt . References: <49DF71CF.7070509@linux.vnet.ibm.com> <20090415194802.GD1382@plap4-2.local> In-Reply-To: <20090415194802.GD1382@plap4-2.local> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2069 Lines: 58 Andrew Vasquez wrote: > On Fri, 10 Apr 2009, jvrao wrote: > >> Qlogic driver uses MSI-EDGE interrupts by default. >> >> On -rt kernel under heavy IO load we observed that the driver missed >> interrupts occasionally. >> >> Missing interrupts caused spurious mailbox timeouts and path failovers. >> >> Suspecting MSI interrupts, we disabled MSI and forcing the driver to use >> APIC interrupts (Patch attached). >> >> With this change, our IO tests ran for extended period of time without >> any issues. >> >> It would be interesting to see if the MSI infrastructure itself has >> issues on realtime, or it is the combination of qla2xxx/MSI. >> >> Right now we don't have any setup to test out MSI with other adapters. >> Hence, wondering if anyone faced similar issues. > > Could you perhaps provide some details on hardware used within your > testing -- HBA type, storage, etc? Also, can you share any logs of > the failures with extended-error-logging enabled > (ql2xextended_error_logging)? Hi, the following link provides more information on the logs and our analysis. https://bugzilla.redhat.com/show_bug.cgi?id=466903 [root@elm3c29 R2-SR1]# lspci | grep -i qlogic 03:05.0 Fibre Channel: QLogic Corp. ISP2422-based 4Gb Fibre Channel to PCI-X HBA (rev 02) 03:05.1 Fibre Channel: QLogic Corp. ISP2422-based 4Gb Fibre Channel to PCI-X HBA (rev 02) Storage is DS4700 (Product ID: 1814) If you need more information, please let me know, I can generate more information/logs. I will also find time to reproduce this with ql2xextended_error_logging enabled. Thanks, JV > > Regards, > Andrew Vasquez > -- > To unsubscribe from this list: send the line "unsubscribe linux-rt-users" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html -- 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/