Russ Arcuri wrote:
> Hi all,

> Two questions:
> 
> 1. What's the current status on scsi dma?

I have an implementation that does DMA to/from a 4k bounce buffer. However, 
NetBSD is capable of more than this. I am currently trying to convert the code 
to use bus_dma() so that the driver can DMA directly to/from the memory where 
the data needs to go, rather than having to go through the bounce buffer (and 
the attendant bcopy's) first.

I have converted my code to use bus_dma and I'm debugging it. The last time I 
worked on it, I was having a problem where the data was being DMAed into the 
buffer at the lowest level but no data seemed to appear to levels above (like 
the generic SCSI code). I think there's a wrong address somewhere but I'm not 
sure where it is.

I'd like to work on this ASAP, but work and home life have been taking 
precidence lately. I hope to get some time to work on this in the next couple of 
months.

Stay up to date on the NetBSD list. I'll post any announcements here.

> 2. What's the real-world disk performance like on the Quadra 840AV with the current (1.5.3) 
> distribution?  I'm trying to decide whether a Quadra 700 or 840AV would be more suitable for 
> my purposes.

The performance of the AV's using the current PIO driver is abysmal.

I suggest you setup your stuff on the Q700 for now and, when DMA becomes 
available, move your setup to the Q840AV later. I think the speed increase of 
DMA should be worth it.

Before I release any code I'll see if I can run some bonnie benchmarks.

-- 
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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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