Re: [rfc] direct IO submission and completion scalability issues

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To: Arjan van de Ven <arjan@...>
Cc: David Chinner <dgc@...>, Nick Piggin <npiggin@...>, Siddha, Suresh B <suresh.b.siddha@...>, <linux-kernel@...>, <mingo@...>, <ak@...>, <jens.axboe@...>, <James.Bottomley@...>, <andrea@...>, <clameter@...>, <akpm@...>, <andrew.vasquez@...>, <willy@...>, Zach Brown <zach.brown@...>
Date: Monday, February 4, 2008 - 12:40 am

On Sun, Feb 03, 2008 at 08:14:45PM -0800, Arjan van de Ven wrote:

Applications as in "anything that calls submit_bio()". i.e, direct I/O,
filesystems, etc. i.e. not userspace but in-kernel applications.

In XFS, simultaneous io completion on multiple CPUs can contribute greatly to
contention of global structures in XFS. By controlling where completions are
delivered, we can greatly reduce this contention, especially on large,
mulitpathed devices that deliver interrupts to multiple CPUs that may be far
distant from each other.  We have all the state and intelligence necessary
to control this sort policy decision effectively.....

Cheers,

Dave.
-- 
Dave Chinner
Principal Engineer
SGI Australian Software Group
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Messages in current thread:
[rfc] direct IO submission and completion scalability issues, Siddha, Suresh B, (Fri Jul 27, 9:21 pm)
Re: [rfc] direct IO submission and completion scalability is..., David Chinner, (Mon Feb 4, 12:40 am)
Re: [rfc] direct IO submission and completion scalability is..., Christoph Lameter, (Mon Jul 30, 2:20 pm)