Re: [PATCH 4/8] x86: add support for remotely triggering the block softirq

Jens Axboe
2008-02-07T10:31:49Z

On Thu, Feb 07 2008, Ingo Molnar wrote:
>
> * Jens Axboe <jens.axboe@oracle.com> wrote:
>
> > > on the more conceptual level, shouldnt we just move to threads
> > > instead of softirqs? That way you can become affine to any CPU and
> > > can do cross-CPU wakeups anytime - which will be nice and fast via
> > > the smp_reschedule_interrupt() facility.
> >
> > That would indeed be nicer and not require any arch changes. I was
> > afraid it would be more costly than massaging the softirqs a bit
> > though, perhaps that is unfounded.
>
> pick up the threaded softirq patches from -rt, those move all softirqs
> processing into kernel threads. I'd suggest to extend those via
> wakeup-from-remote functionality - it fits the construct quite
> naturally. You should also be able to directly observe any performance
> impact of threaded softirq handlers. (and if you find any, let me know
> so that we can make it faster :-)

I was just considering that, since I knew -rt moved the softirqs into
threads. I'll look into it, but may not post anything until after my
vacation.

--
Jens Axboe