Re: memove performance of NetBSD

[Manuel Bouyer <bouyer%antioche.eu.org@localhost>]

On Fri, Jan 22, 2010 at 02:37:21PM +0530, Channa wrote:
> Hi ,
> I am using NetBSD 3.1 ,I have some issues with the performance of memmove().
> 
> The memmove() implementation in NetBSD has the following algorithm
> <1> If the source is aligned then copy 8*4 bytes at a time to destination
> <2> If the source is unaligned then the copy is done byte by byte
> 
> [...]
> Due to which the performance of memmove() degrades when the source is 
> unaligned.
> 
> I feel the algorithm could be changed as below:
> 
> <2> If the source is unaligned then copy the only some bytes of source
> to destination so that source is at an aligned address, then copy 8*4
> bytes at a time.
> 
> The above step could increase the performance of memmove() for
> unaligned source address.
> 
> Please let me know your opinion on my views.

Did you check the code used by netbsd-5 ? This may have been changed
since netbsd-3 was branched.

-- 
Manuel Bouyer <bouyer%antioche.eu.org@localhost>
     NetBSD: 26 ans d'experience feront toujours la difference
--