Re: Lower HD transfer rate with NCQ enabled?

From: Bill Davidsen
Date: Fri Apr 06 2007 - 17:31:42 EST


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?

It suggests that it's time to test with real load and see if deadline works well for you in the general case.

--
Bill Davidsen <davidsen@xxxxxxx>
"We have more to fear from the bungling of the incompetent than from
the machinations of the wicked." - from Slashdot
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