Messages in this thread | | | From | Jeff Moyer <> | Subject | Re: [PATCH] cfq-iosched: non-rot devices do not need read queue merging | Date | Tue, 05 Jan 2010 16:19:08 -0500 |
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Vivek Goyal <vgoyal@redhat.com> writes:
> Thanks Jeff, one thing comes to mind. Now with recent changes, we drive deeper > depths on SSD with NCQ and there are not many pending cfqq on service tree > until and unless number of parallel threads exceed NCQ depth (32). If > that's the case, then I think we might not be seeing lot of queue merging > happening in this test case until and unless dump utility is creating more > than 32 threads. > > If time permits, it might also be interesting to run the same test with queue > depth 1 and see if SSDs without NCQ will suffer or not.
Corrado, I think what Vivek is getting at is that you should check for both blk_queue_nonrot and cfqd->hw_tag (like in cfq_arm_slice_timer). Do you agree?
Cheers, Jeff
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