Re: high load, no bottleneck

[Manuel Bouyer <bouyer%antioche.eu.org@localhost>]

On Sat, Sep 21, 2013 at 12:01:45PM +0200, Edgar Fuß wrote:
> > I suspect that indeed, while a fluch cache command is running, the
> > disk is not considered busy. Only read and write commands are tracked.
> Would it a) make sense b) be possible to implement that flushes are counted 
> as busy?

It would probably make sense. But requires a bit of work:
right now, disk_busy()/disk_unbusy() takes as argument the byte count and
the op type (read/write). I think we should separate flushes from writes
so that writes don't get counted twice (also byte count cannot be
guessed for flushes, we don't know how much data there's in the disk cache).
Maybe we could count flushes as 0-byte writes, but I'm not sure that
disk_busy()/disk_unbusy() would handle this properly.
Or we could add a third operation type, but then disk_busy()/disk_unbusy()
and userland tools would need to be chanegd to handle it ...

-- 
Manuel Bouyer <bouyer%antioche.eu.org@localhost>
     NetBSD: 26 ans d'experience feront toujours la difference
--