Re: memcpy_toio on i386 using byte writes even when n%2==0

[H. Peter Anvin]

Followup to:  <447CE99B.7070707@xxxxxxx>
By author:    Robert Hancock <hancockr@xxxxxxx>
In newsgroup: linux.dev.kernel
> > 
> > Note that there isn't any code for moving dwords because the
> > chances of gaining anything are slim (alignment may hurt).
> 
> I'd say the chances of gaining something from executing half as many 
> instructions on copying a large block of memory are very good indeed..
> 

For something that generates I/O transactions, it's imperative to
generate the smallest possible number of transactions.  Furthermore,
smaller than dword transactions aren't burstable, except at the
beginning and end of a burst.

	-hpa

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