Larson, Tim (Corporate) wrote:

> Did you do any benchmarks of a stock system vs your patched version?

I ran bonnie on a stock system before the patch (using PIO) and after 
the patch. I don't have the results on me as I'm at work right now, but 
if you peruse the mailinglist archives you should be able to find a post 
from me with the results. Basically, without any of the enhancements 
that I mentioned, there was only a slight speedup in writes (or reads, I 
forget).

Though, it probably wasn't the best benchmarking ever. I'd be curious if 
somebody could really stress the patch with much larger files and see 
what happens.

> And how much slower is it than other systems?

With just PIO, it has to be slower than a non-AV Quadra since non-AV 
Quadras use a sort of pseudo-DMA speed up. The non-AV Quadras have this 
interesting block of registers that the CPU can read and write from that 
tickle the NCR chip in the same way a DMA controller might. So the 
non-AV Quadras can push/pull data to the NCR at a much higher rate than 
machines without this enhancement. Though, you consume lots of CPU doing 
this. Basically, it's DMA without the DMA. :)

I haven't done any benchmarks to confirm the difference but it makes 
sense from an intuitive point of view that the non-AV's would be much 
faster than the AV's at the moment.

Don't get me wrong, the AV will _work_ but it's not going to give 
stellar disk performance without the changes I mentioned in my last 
email, even with my patch to use the DMA engine.

> Do you provide the patched version in binary form so people can try
> it out?

I don't have a binary handy. I submitted the patch to the email list (so 
it should be in the archives) and in a Problem Request so that it gets 
applied to the mainline kernel. I asked about it making it in recently 
and one of the maintainers mentioned that he'd like to get it in when he 
has some time. Though, it's important to keep in mind that things move 
really slowly around here :) 68k stuff like this is real back-burner 
hobby kind of stuff :)

If you're not a big driver guy, though, I would wait until my patch 
makes it into the tree or wait until somebody updates my driver with the 
optimizations I was talking about.

-- 
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  Michael Zucca - mrz5149@acm.org
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  "I'm too old to use Emacs." -- Rod MacDonald
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