linux-kernel - Re: Why is NCQ enabled by default by libata? (2.6.20)

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite for Android: free password hash cracker in your pocket

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:	Tue, 27 Mar 2007 05:55:44 -0400 (EDT)
From:	Justin Piszcz <jpiszcz@...idpixels.com>
To:	Alan Cox <alan@...rguk.ukuu.org.uk>
cc:	linux-kernel@...r.kernel.org
Subject: Re: Why is NCQ enabled by default by libata? (2.6.20)

On Sat, 24 Mar 2007, Alan Cox wrote:

> On Sat, 24 Mar 2007 12:38:02 -0400 (EDT)
> Justin Piszcz <jpiszcz@...idpixels.com> wrote:
>
>> Without NCQ, performance is MUCH better on almost every operation, with
>> the exception of 2-3 items.
>
> It depends on the drive. Generally NCQ is better but some drive firmware
> isn't too bright and there are probably still cases where we get bad
> interactions in the kernel code that want tuning too
>

Checking the benchmarks on various hardware websites, anandtech, 
hothardware and others, they generally all come to the same conclusion if 
there is only 1 thread using I/O (single user system) then NCQ off is the 
best.  I see 30-50MB/s faster speeds with NCQ turned off on two different 
SW RAID5s.

Justin.
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/