RE: Cache queue_congestion_on/off_threshold

Chen, Kenneth W
2004-05-06T20:31:10Z

>>>> Jens Axboe wrote on Wed, May 05, 2004 11:43 PM
> On Wed, May 05 2004, Andrew Morton wrote:
> > Jens Axboe <axboe@suse.de> wrote:
> > >
> > > Do you have any numbers at all for this? I'd say these calculations are
> > > severly into the noise area when submitting io.
> >
> > The difference will not be measurable, but I think the patch makes sense
> > regardless of what the numbers say.
>
> Humm dunno, I'd rather save the sizeof(int) * 2.

Strictly speaking from memory consumption point of view, it probably comes
for free since sizeof(struct request_queue) currently is 456 bytes on x86
and 816 on 64bit arch. The structure is being rounded to 512 or 1024 with
kmalloc. If it is on the borderline to next kmalloc size, it probably should
be revisited. But so far it has been noise on the positive side.

- Ken