Messages in this thread | | | Date | Tue, 27 Nov 2001 09:38:00 +0100 | From | Jens Axboe <> | Subject | Re: Unresponiveness of 2.4.16 |
| |
On Tue, Nov 27 2001, Andrew Morton wrote: > Jens Axboe wrote: > > > > I agree that the current i/o scheduler has really bad interactive > > performance -- at first sight your changes looks mostly like add-on > > hacks though. > > Good hacks, or bad ones? > > It keeps things localised. It works. It's tunable. It's the best > IO scheduler presently available.
Hacks look ok on cursory glances :-)
> > Arjan's priority based scheme is more promising. > > If the IO priority becomes an attribute of the calling process > then an approach like that has value. For writes, the priority > should be driven by VM pressure and it's probably simpler just > to stick the priority into struct buffer_head -> struct request. > For reads, the priority could just be scooped out of *current. > > If we're not going to push the IO priority all the way down from > userspace then you may as well keep the logic inside the elevator > and just say reads-go-here and writes-go-there.
Priority will be passed down for reads as you suggest, at least that is the intention I had as well. I've only worked on 2.5 with this, but I guess we can find some space in the buffer_head to squeeze in some priority bits.
> But this has potential to turn into a great designfest. Are
Oh yeah
> we going to leave 2.4 as-is? Please say no.
I'd be happy to review anything you come up with -- or in other works, feel free to knock yourself out, I'm busy with other stuff currently :)
-- Jens Axboe
- 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/
| |