Paa Paa wrote:
Q: What conclusion can I make on "hdparm -t" results or can I make
any conclusions? Do I really have lower performance with NCQ or not?
If I do, is this because of my HD or because of kernel?
What IO scheduler are you using? If AS or CFQ, could you try with
deadline?
I was using CFQ. I now tried with Deadline and that doesn't seem to
degrade the performance at all! With Deadline I got 60MB/s both with and
without NCQ. This was with "hdparm -t".
So what does this tell us?
Thanks. I believe CFQ contains some code to keep NCQ depths managable,
which might be causing the problem. I've cc'ed the CFQ author (Jens)
who might be able to give some more ideas.
Thanks for reporting!
--
SUSE Labs, Novell Inc.
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