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From: Mark Lord <liml@rtr.ca>
To: Gentoopower <gentoopower@yahoo.de>
Cc: "linux-ide@vger.kernel.org" <linux-ide@vger.kernel.org>
Subject: Re: NCQ general question
Date: Wed, 01 Mar 2006 13:34:38 -0500	[thread overview]
Message-ID: <4405E93E.3010307@rtr.ca> (raw)
In-Reply-To: <4405D040.8000700@yahoo.de>

Gentoopower wrote:
> Jens Axboe wrote:
>> On Wed, Mar 01 2006, Gentoopower wrote:
..
>>> I can defintely feel the speed difference between the two drives.
>>>     
>> Well that can't be because of NCQ, since it isn't active :-)   
> 
> Got ya:-)
> 
> Who said this box is running only linux?

You did, by posting to the *Linux-IDE* kernel mailing list.

All bets are off for other OSs, especially those that really
*need* NCQ for half-decent performance.

Linux doesn't, but it's definitely nice to wish for.

I've implemented host-queuing support for NCQ and TCQ on
several controllers (for Linux), and it almost always produces
only a tiny *measureable* effect on desktop systems.

Busy servers, with lots of teensy random read requests,
benefit most from it, as do benchmark programs that do a lot of seeking.

But normal system use -- running OO.org, rebuilding kernels,
etc.. no significant measurable difference.  Maybe by fiddling
with the IO scheduler code (which defeats NCQ/TCQ to a degree)..

But I'd happily enable it on my own systems anyway!

Cheers

      reply	other threads:[~2006-03-01 18:34 UTC|newest]

Thread overview: 26+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2006-03-01  7:04 NCQ general question Raz Ben-Jehuda(caro)
2006-03-01  8:56 ` Gentoopower
2006-03-01 13:49   ` Mark Lord
2006-03-01 13:55     ` Jens Axboe
2006-03-03 21:55       ` Steve Byan
2006-03-03 22:19         ` Jeff Garzik
2006-03-04 18:56           ` Steve Byan
2006-03-04 19:10             ` Jeff Garzik
2006-03-04 20:23               ` Steve Byan
2006-03-04 23:56                 ` Eric D. Mudama
2006-03-05  7:19                   ` Raz Ben-Jehuda(caro)
2006-03-05  7:29                     ` Jeff Garzik
2006-03-01 15:56     ` Gentoopower
2006-03-01 16:05       ` Jens Axboe
2006-03-01 16:20         ` Jeff Garzik
2006-03-01 18:53           ` Jens Axboe
2006-03-02  8:14             ` Raz Ben-Jehuda(caro)
2006-03-02  8:18               ` Jens Axboe
2006-03-02 11:20                 ` Jeff Garzik
2006-03-02 13:34                   ` Raz Ben-Jehuda(caro)
2006-03-02 13:37                     ` Jeff Garzik
2006-03-02  8:18           ` Rafal Krzewski
2006-03-02 11:35             ` Jeff Garzik
2006-03-02 14:29               ` Rafal Krzewski
2006-03-01 16:48         ` Gentoopower
2006-03-01 18:34           ` Mark Lord [this message]

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