From: Mark Lord <liml@rtr.ca>
To: Andrew Lyon <andrew.lyon@gmail.com>
Cc: linux-ide@vger.kernel.org, Alan Cox <alan@redhat.com>,
Tejun Heo <htejun@gmail.com>
Subject: Re: ahci problems with sata disk.
Date: Tue, 16 Jan 2007 13:32:26 -0500 [thread overview]
Message-ID: <45AD1A3A.4000706@rtr.ca> (raw)
In-Reply-To: <f4527be0701160844r19fe5220i39a5834f1f4df570@mail.gmail.com>
..
>> I though that NCQ was intended to increase performance ??
..
> My Raptor drive WDC WD740ADFD-00 Rev: 20.0 performs worse with NCQ
> than with NCQ, Alan Cox has added it to a blacklist but I dont think
> that is in the mainline kernel yet.
>
> Search the list archives for my previous postings about it, including
> some hdparm -tT results.
>
> Andy
Raptors have "server style" firmware in them.
When NCQ is turned on, they self-optimize for random seeks
rather than for sequential read-ahead.
My hdparm test is a sequential read-ahead test, so it will
naturally perform worse on a Raptor when NCQ is on.
That doesn't mean NCQ is bad on all Raptors; it just means
it's not good for large sequential reads.
Cheers
next prev parent reply other threads:[~2007-01-16 18:32 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-01-14 14:32 ahci problems with sata disk kenneth johansson
2007-01-15 9:13 ` Tejun Heo
2007-01-15 11:05 ` kenneth johansson
2007-01-15 11:36 ` Alan
2007-01-15 13:50 ` Tejun Heo
2007-01-16 1:43 ` kenneth johansson
2007-01-16 16:44 ` Andrew Lyon
2007-01-16 18:32 ` Mark Lord [this message]
2007-01-16 20:20 ` Mark Hahn
2007-01-16 22:10 ` Jeff Garzik
2007-01-16 22:26 ` Eric D. Mudama
2007-01-17 22:03 ` Jens Axboe
2007-01-17 22:03 ` Jens Axboe
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