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Post subject: IP over PCI
 Posted: Dec 04, 2007 - 10:59 PM
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New Member
Joined: Jul 26, 2005
Posts: 2
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I wonder if anyone ever heard of QNX6 implementation of the driver in subject. I remember seeing something similar on QNX'2000 in Vancuver, Canada back in 2000, but never heard anything since.
The idea behind this question is to have several single board computers(sitting in the same cPCI chassis) communicating to each other without physical Ethernet connection.
Thanks in advance. |
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Post subject: RE: IP over PCI
Posted: Dec 05, 2007 - 12:05 AM
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QNX Master
Joined: Sep 01, 2002
Posts: 2667
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I *think* there was a driver for that, never released though. The problem with that is it's very heavy on the CPU time, what is usually done via DMA on the network card has to be handle by the CPU. Take for example a broadcast in TCP/IP (ARP) or as use by QNET. It means the driver has to copy the data to every other board one by one... Also backplane can become create a huge bottle neck. The PCI bus can only handle 133Mbytes sec at best ( if not done by DMA it can drop dramatically). But that 133Mbytes is shared with ALL the CPU card, has opposed to a good 1G network switch that can handle a lot more then 1G/sec.
If the CPU are dual core then it might not be as bad cause one core can take care of the networking but I'm guessing speedwise it will crawl.
I think there is something about rapid IO though that might be of help. |
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Post subject: RE: IP over PCI
Posted: Dec 05, 2007 - 05:36 PM
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New Member
Joined: Jul 26, 2005
Posts: 2
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Mario, thank you for helpful hints. System this driver is intended to go will have very light traffic of control messages going between boards. So neither CPU nor through output issues matter. Benefit though is that system design relies on IP communication and will not require any changes when Ethernet connection becomes available.
Do you know by any chance whom in QNX I can talk to to get binaries or even source code of mentioned driver? I recall Sebastian was presenting this feature in Vancuver, but he is kind of not in the development anymore I guess. |
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Post subject: RE: IP over PCI
Posted: Dec 05, 2007 - 09:36 PM
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QNX Master
Joined: Sep 01, 2002
Posts: 2667
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Normal channel is sales, unfortunately  Try posting in foundry 27 networking forum.
A driver like that shouldn't be that difficult to write. |
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Post subject: RE: IP over PCI
Posted: Dec 06, 2007 - 01:00 PM
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Senior Member
Joined: Apr 07, 2005
Posts: 257
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| Have you tried asking about this on Foundry27 ? There is a Networking Project with Forums. |
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Post subject: Re: RE: IP over PCI
Posted: Dec 09, 2007 - 03:46 PM
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QNX Master
Joined: Jul 11, 2002
Posts: 557
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maka111 wrote:
Mario, thank you for helpful hints. System this driver is intended to go will have very light traffic of control messages going between boards. So neither CPU nor through output issues matter. Benefit though is that system design relies on IP communication and will not require any changes when Ethernet connection becomes available.
Do you know by any chance whom in QNX I can talk to to get binaries or even source code of mentioned driver? I recall Sebastian was presenting this feature in Vancuver, but he is kind of not in the development anymore I guess.
There is a rapidIO driver, but not a PCI(x) driver. The logical hardware to target for this is PCI Express, which is functionally similar to rapidIO, but this has not been done yet. |
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