Subject: Re: copyin/out
To: David Laight <firstname.lastname@example.org>
From: Jason R Thorpe <email@example.com>
Date: 08/09/2002 12:46:33
On Fri, Aug 09, 2002 at 08:31:34PM +0100, David Laight wrote:
> However those were for very large transfers.
> What happens for small transfers where all the 'red tape'
> becomes more significant than the innermost loop.
> Even 128 or 512 bytes might be significantly slower.
Well... if you take a look at the current copyin/copyout, I'm not
sure you can convince me that the new one would be significantly
*slower*. The current one is ... really brain-dead.
> I expect that certain workloads contain a significant number
> of short transfers. It is probably possible to test misalgned
> transfers using mismatched ibs and obs values.
In the near future, we plan on writing some code that will give us a
histogram of copyin/copyout activity.
-- Jason R. Thorpe <firstname.lastname@example.org>