Re: [GIT PULL] Core block IO bits for 2.6.39

Alan Cox
2011-03-27T13:21:55Z

On Sat, 26 Mar 2011 09:48:37 -0700
Linus Torvalds <torvalds@linux-foundation.org> wrote:

> On Fri, Mar 25, 2011 at 11:29 PM, Jens Axboe <jaxboe@fusionio.com> wrote:
> > +
> > +       /* Use 3ms as that was the old plug delay */
> > +       blk_delay_queue(q, msecs_to_jiffies(3));
>
> That's bogus. blk_delay_queue() already takes msecs, not jiffies.
>
> Also, do we really need to delay every unplug like this? It seems sad.
> A 3ms delay is a long time these days - admittedly most people
> hopefully use ATA these days if they have an SSD or something, but
> still..

The ATA code contains several other bogus delays btw. So out of the box
unless you are using AHCI you are continually running small pointless
delays every command issued.