linux-kernel - Re: high-speed disk I/O is CPU-bound?

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

Date:	Sun, 12 May 2013 11:53:37 -0500
From:	Rob Landley <rob@...dley.net>
To:	David Oostdyk <daveo@...mit.edu>
Cc:	linux-kernel@...r.kernel.org
Subject: Re: high-speed disk I/O is CPU-bound?

On 05/10/2013 09:04:44 AM, David Oostdyk wrote:
> Hello,
> 
> I have a few relatively high-end systems with hardware RAIDs which  
> are being used for recording systems, and I'm trying to get a better  
> understanding of contiguous write performance.
...
> The question is, is it possible that high-speed I/O to these hardware  
> RAIDs could
> actually be CPU-bound above ~1400MB/sec?

In some setups your processor is calculating CRCs for the data. It's a  
fairly cheap operation, but a cheap operation on gigabytes of data can  
still saturate your memory bus.

Rob--
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/