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. Hmm. Can we get down to the root cause of that problem instead of applying a bandaid patch ? If -rt has problems with MSI edge interrupts then we really need to figure out why. If the qlogic driver has problems with the different timings of -rt then we need to fix that one. Thanks, tglx -- To unsubscribe from this list: send the line "unsubscribe linux-rt-users" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
