Of all the gin joints in all the towns in all the world, Kenneth D. Merry had
to walk into mine and say: >
> [ Thanks for the info Bill! ]
No problemo.
[...]
> > Both the Alteon and SysKonnect NICs are 64-bit PCI cards. (Actually, I'm
> > pretty sure all of the PCI gigabit NICs are 64-bit.) Both kinds of cards
> > can do jumbograms on FreeBSD. Also, both vendors have released pretty good
> > hardware documentation, which makes them good choices for custom applications,
> > if you're into that sort of thing.
>
> Alteon also provides firmware source, which can really come in handy. Do
> you know if SysKonnect has released firmware?
The SysKonnect GEnesis controller and the XaQti XMAC II chips are both static
devices and do not require firmware. If you go to www.syskonnect.com and
search their online knowledge base for the word "manual" you should be
able to find the gigabit NIC programmer's manual. Similarly, XaQti has
the full datasheet for the XMAC II at www.xaqti.com somewhere. (As I recall,
you have to go through a brief registration procedure to get it, but once
that's done you should be able to download it right away.)
Talking of the XMAC II, there's one other thing I forgot to mention earlier.
The FreeBSD sk driver does jumbo frames, but the SysKonnect drivers don't.
At least, not yet. The XMAC II's receive FIFO is 8K. By default, the chip
operates in 'store and forward' mode in order to perform error checking on
received frames (it has to get the entire frame in the FIFO in order to
do a CRC on it, I think). This is fine for normal frames, but if you want
to handle jumbograms larger than 8192 bytes, you have to put the chip into
'streaming' mode, otherwise any frame larger than 8192 bytes will be truncated.
To get 'streaming' mode to work, you have to disable all of the RX error
checking.
Also, the default TX FIFO threshold on the XMAC is very small (8 bytes, I
think). The FreeBSD sk driver bumps this up a bit (to 512 bytes, if I
remember correctly). This is to deal with the case where you have a dual
port card and are pumping data through both XMAC chips at once: with the
default FIFO threshold, I would often see TX FIFO underruns from one of
the XMACs and performance on that port would get spotty. I think the total
TX FIFO memory on the XMAC II is 2K.
-Bill
--
=============================================================================
-Bill Paul (212) 854-6020 | System Manager, Master of Unix-Fu
Work: [EMAIL PROTECTED] | Center for Telecommunications Research
Home: [EMAIL PROTECTED] | Columbia University, New York City
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"It is not I who am crazy; it is I who am mad!" - Ren Hoek, "Space Madness"
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