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: Windows password security audit tool. GUI, reports in PDF.
[<prev] [next>] [thread-next>] [day] [month] [year] [list]
Message-ID: <Pine.LNX.4.64.0705090918390.12857@p34.internal.lan>
Date:	Wed, 9 May 2007 09:22:08 -0400 (EDT)
From:	Justin Piszcz <jpiszcz@...idpixels.com>
To:	axboe@...e.de
cc:	linux-kernel@...r.kernel.org, linux-raid@...r.kernel.org,
	Alan Piszcz <ap@...arrain.com>
Subject: Chaining sg lists for big I/O commands: Question

http://kerneltrap.org/node/8176

I am a mdadm/disk/hard drive fanatic, I was curious:

> On i386, we can at most fit 256 scatterlist elements into a page,
> and on x86-64 we are stuck with 128. So that puts us somewhere
> between 512kb and 1024kb for a single IO.

How come 32bit is 256 and 64 is only 128?
I am sure it is something very fundamental/simple but I was curious, I 
would think x86_64 would fit/support more scatterlists in a page.

Also, when this patch is implemented for x86_64 and if merged into 
mainline, what does this mean for performance?

I have an mdadm raid5 of 10 raptors and get 434MB/s write and 622MB/s 
read, would I see an increase in performance with this patch?

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/

Powered by blists - more mailing lists

Powered by Openwall GNU/*/Linux Powered by OpenVZ