linux-kernel - Interrupts are being dropped under heavy IO on -rt .

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [thread-next>] [day] [month] [year] [list]

Message-ID: <49DF71CF.7070509@linux.vnet.ibm.com>
Date:	Fri, 10 Apr 2009 09:20:31 -0700
From:	jvrao <jvrao@...ux.vnet.ibm.com>
To:	LKML <linux-kernel@...r.kernel.org>,
	rt-users <linux-rt-users@...r.kernel.org>
CC:	Mike Anderson <andmike@...ux.vnet.ibm.com>,
	"Luis Claudio R. Goncalves" <lgoncalv@...hat.com>,
	linux-driver@...gic.com
Subject: Interrupts are being dropped under heavy IO on -rt .

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.

Thanks,
JV

View attachment "qla_nomsi.patch" of type "text/x-patch" (1204 bytes)