Messages in this thread | | | Date | Thu, 3 Dec 2009 13:00:21 +0100 | From | Jens Axboe <> | Subject | Re: [PATCH]cfq-iosched: make nonrot check logic consistent |
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On Thu, Dec 03 2009, Jens Axboe wrote: > On Thu, Dec 03 2009, Shaohua Li wrote: > > Send again, last post seems lost. > > > > cfq_arm_slice_timer() has logic to disable idle window for SSD device. The same > > thing should be done at cfq_select_queue() too, otherwise we will still see > > idle window. This makes the nonrot check logic consistent in cfq. > > Tests in a intel SSD with low_latency knob close, below patch can triple disk > > thoughput for muti-thread sequential read. > > > > Signed-off-by: Shaohua Li <shaohua.li@intel.com> > > --- > > block/cfq-iosched.c | 3 ++- > > 1 file changed, 2 insertions(+), 1 deletion(-) > > > > Index: linux/block/cfq-iosched.c > > =================================================================== > > --- linux.orig/block/cfq-iosched.c 2009-11-11 13:44:00.000000000 +0800 > > +++ linux/block/cfq-iosched.c 2009-11-11 13:45:33.000000000 +0800 > > @@ -1215,7 +1215,8 @@ static struct cfq_queue *cfq_select_queu > > * conditions to happen (or time out) before selecting a new queue. > > */ > > if (timer_pending(&cfqd->idle_slice_timer) || > > - (cfqq->dispatched && cfq_cfqq_idle_window(cfqq))) { > > + (cfqq->dispatched && cfq_cfqq_idle_window(cfqq) > > + && !(blk_queue_nonrot(cfqd->queue) && cfqd->hw_tag))) { > > cfqq = NULL; > > goto keep_queue; > > } > > Thanks, applied to 2.6.33 queue.
On second check, we now hide that logic in cfq_should_idle() and as such your patch no longer applies. I suggest you re-test with -next or my for-2.6.33 branch, it has a big number of pending CFQ updates for 2.6.33.
-- Jens Axboe
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