hifn(4) DMA fix for review

[Sam Leffler]

On May 7, 2010, at 12:13 PM, Oleksandr Tymoshenko wrote:

>    Proposed patch addresses hifn(4) problems on FreeBSD/mips. Current
> implementation keeps some of the state information (indexes in
> buffers, etc) in DMA-mapped memory and bus_dma code invalidates them
> during sync operations. This fix moves data that doesn't belong to DMA
> ring to softc structure.
>
> Patch: http://people.freebsd.org/~gonzo/hifn.diff
> Stats for original driver:
>    http://people.freebsd.org/~gonzo/hifn.stats.orig.txt
> Stats for patched version:
>    http://people.freebsd.org/~gonzo/hifn.stats.patched.txt
>
>

The changes look fine and make sense (did something similar for some  
other drivers for when the dma data structures were mapped uncached).   
I can't see any performance change in your stats; but I'm just  
eyeballing the numbers side-by-side.  Was this on x86? (where there  
should be zero difference)  It would be good to present these numbers  
better (e.g. curves on the same graph, ministat output, etc).

	Sam