Re: [PATCH]cfq-iosched: don't stop async queue with async requestspending

[Shaohua Li]

On Wed, Jan 13, 2010 at 04:18:47PM +0800, Corrado Zoccolo wrote:
> On Wed, Jan 13, 2010 at 8:44 AM, Shaohua Li <shaohua.li@xxxxxxxxx> wrote:
> > My SSD speed of direct write is about 80m/s, while I test page writeback,
> > the speed can only go to 68m/s. Below patch fixes this.
> > It appears we missused cfq_should_idle in cfq_may_dispatch. cfq_should_idle
> > means a queue should idle because it's seekless sync queue or it's the last queue,
> > which is to maintain service tree time slice. So it doesn't mean the
> > last queue is always a sync queue. If the last queue is asyn queue,
> > we definitely shouldn't stop dispatch requests because of pending async
> > requests.
> 
> An other option is that cfq_should_idle returns false for async
> queues, since cfq will never idle on them.
I'm considering this option too, but it appears we need make async queue
idle to maintain domain time slice.

Thanks,
Shaohua
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/