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* [PATCH] cfq-iosched: fix think time allowed for seekers
@ 2009-10-07  9:00 Corrado Zoccolo
  2009-10-07 17:48 ` Jens Axboe
  0 siblings, 1 reply; 2+ messages in thread
From: Corrado Zoccolo @ 2009-10-07  9:00 UTC (permalink / raw)
  To: Linux-Kernel, Jens Axboe, Jeff Moyer

CFQ enables idle only for processes that think less than the allowed
idle time. Since idle time is lower for seeky queues, we should use the
correct value in the comparison.

Signed-off-by: Corrado Zoccolo <czoccolo@gmail.com>
---
 block/cfq-iosched.c |    5 ++++-
 1 files changed, 4 insertions(+), 1 deletions(-)

diff --git a/block/cfq-iosched.c b/block/cfq-iosched.c
index 55bb8ca..4c795a2 100644
--- a/block/cfq-iosched.c
+++ b/block/cfq-iosched.c
@@ -1997,7 +1997,10 @@ cfq_update_idle_window(struct cfq_data *cfqd, struct cfq_queue *cfqq,
 	    (!cfqd->cfq_latency && cfqd->hw_tag && CIC_SEEKY(cic)))
 		enable_idle = 0;
 	else if (sample_valid(cic->ttime_samples)) {
-		if (cic->ttime_mean > cfqd->cfq_slice_idle)
+		unsigned int slice_idle = cfqd->cfq_slice_idle;
+		if (sample_valid(cic->seek_samples) && CIC_SEEKY(cic))
+			slice_idle = msecs_to_jiffies(CFQ_MIN_TT);
+		if (cic->ttime_mean > slice_idle)
 			enable_idle = 0;
 		else
 			enable_idle = 1;
-- 
1.6.2.5



^ permalink raw reply related	[flat|nested] 2+ messages in thread

* Re: [PATCH] cfq-iosched: fix think time allowed for seekers
  2009-10-07  9:00 [PATCH] cfq-iosched: fix think time allowed for seekers Corrado Zoccolo
@ 2009-10-07 17:48 ` Jens Axboe
  0 siblings, 0 replies; 2+ messages in thread
From: Jens Axboe @ 2009-10-07 17:48 UTC (permalink / raw)
  To: Corrado Zoccolo; +Cc: Linux-Kernel, Jeff Moyer

On Wed, Oct 07 2009, Corrado Zoccolo wrote:
> CFQ enables idle only for processes that think less than the allowed
> idle time. Since idle time is lower for seeky queues, we should use the
> correct value in the comparison.

Looks good, applied. Thanks!

-- 
Jens Axboe


^ permalink raw reply	[flat|nested] 2+ messages in thread

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2009-10-07  9:00 [PATCH] cfq-iosched: fix think time allowed for seekers Corrado Zoccolo
2009-10-07 17:48 ` Jens Axboe

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