cfq-iosched: make nonrot check logic consistent
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>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
diff --git a/block/cfq-iosched.c b/block/cfq-iosched.c
index 43ec334..b00ca4c 100644
--- a/block/cfq-iosched.c
+++ b/block/cfq-iosched.c
@@ -1796,7 +1796,8 @@
return false;
/* We do for queues that were marked with idle window flag. */
- if (cfq_cfqq_idle_window(cfqq))
+ if (cfq_cfqq_idle_window(cfqq) &&
+ !(blk_queue_nonrot(cfqd->queue) && cfqd->hw_tag))
return true;
/*
