Re: [PATCH] qla2xxx: Resolved a performance issue in interrupt handler

James Bottomley
2009-06-10T16:17:59Z

On Wed, 2009-06-10 at 09:09 -0700, Anirban Chakraborty wrote:
> On Jun 10, 2009, at 8:52 AM, Styner, Douglas W wrote:
>
> >
> > Anirban Chakraborty [mailto:anirban.chakraborty@qlogic.com] write:
> >>
> >> You got it right. Basically we are doing:
> >> 1. baseline scsi-misc + earlier patch
> >> 2. baseline scsi-misc + this patch
> >> And then compare 1 and 2.
> >
> > Results are as follows:
> > Total interrupts are down slightly (-0.8%), QLA interrupts are flat
> > (-0.1%) Cycles for qla2xxx_intr_handler up from .77% to .92%.
>
> So, it looks like using spin_lock_irqsave is doing a better job than
> globally disabling the sharing of the interrupt via IRQF_DISABLED.

OK, so just drop the msix changes and resubmit ... it'll have to go in
SCSI misc, but once the merge window is over, you can request a backport
to stable.

James