Re: xmm2 - monitor Linux MM active/inactive lists graphically

[Jens Axboe]

On Fri, Oct 26 2001, Zlatko Calusic wrote:
> Linus Torvalds <[e-mail]> writes:
> 
> > On 25 Oct 2001, Zlatko Calusic wrote:
> > >
> > > Yes, I definitely have DMA turned ON. All parameters are OK. :)
> > 
> > I suspect it may just be that "queue_nr_requests"/"batch_count" is
> > different in -ac: what happens if you tweak them to the same values?
> > 
> 
> Next test:
> 
> block: 1024 slots per queue, batch=341

That's way too much, batch should just stay around 32, that is fine.

> Still very spiky, and during the write disk is uncapable of doing any
> reads. IOW, no serious application can be started before writing has
> finished. Shouldn't we favour reads over writes? Or is it just that
> the elevator is not doing its job right, so reads suffer?

You are probably just seeing starvation due to the very long queues.

-- 
Jens Axboe