Have you tried to use the SIMD extensions to speed up the transfer ? Intel
has some cool sample code for that kind of thing. Also, 300K times 30 is 9M,
well, the rated PCI bus speed is 33Mhz and that’s four bytes at a time,
should be plenty of bandwidth to move your data within your time spec.
Mapping your board’s memory aperture to be visible by the application can be
done, but it’s messy.
The other thing you can do is to handle all your data within the driver,
including the file management. We do that with our driver-intensive
applications (such as performance measurement and coverage data collection)
and it works ok: keep the data in the kernel side and use your app just as a
GUI front-end.
Hope this helps !
Alberto.
-----Original Message-----
From: xxxxx@hotmail.com [mailto:xxxxx@hotmail.com]
Sent: Monday, March 31, 2003 11:49 PM
To: NT Developers Interest List
Subject: [ntdev] Re: Passing a pointer from the driver back to the user
Hi Maxim and Walter,
Thank you for the replies.
My main reason for asking if a pointer could be passed back from the
driver was because I want to achieve very fast reads and writes (about 30
a second). I am a student and am in my final year of study and my final
year project was to first program a PCI (using an FPGA) and then
interfacing with the card through a windows driver. Perhaps you can point
me in the right direction then.
I am trying to acheive reads from 307200 registers each time but I need to
pass this data back to my user application about 30 times a second. Can
you suggest the best and fastest way for this transfer to happen? I am
relunctant to use DMA because it would require many modifications to our
hardware.
I appreciate any suggestions!
Thanks,
Wynn
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