Myrinet vs. Dolphin

[Jared Hodge]

I was wondering if anyone has experience with Dolphin Interconnect
Solutions (http://www.dolphinics.com)?  We currently have Myrinet
(www.myri.com) on our cluster and it seems to be working reasonably
well.  I have several questions though.  First, we are considering
upgrading our cluster with more nodes, and myrinet seems to have a
scalability problem in the average cluster size area.  We have 8 nodes
now, and can go up to 16 nodes with our current switch, but past that,
Myricom says we would need one additional switch to get up to 18 nodes
and two additional switches to get up to 24.  Ok, we just went from
spending $5000 on JUST SWITCHES to $15000, and we didn't even get close
to the 32 nodes we were thinking about.  I know they have there $40,000
Millionare-in-a-box, I mean network-in-a-box "solution", but really who
wants to waste that much money (if I just need even 32 nodes). Not to
mention that Myrinet prices have not come down in... ah, ever as far as
I can tell.  Dolphin's switchless technology appears inviting in this
area, but I don't know if it has really been proven in the Beowulf
area.  I also don't know how much Dolphin equipment costs (I just sent a
request in for pricing).  From the specs that I've seen, I think Dolphin
is supposed to be faster as far as latency, but slower as far as
bandwidth, but I rarely trust specs from manufacturers, and was
wondering if any of you have run comparison tests.  From what I've seen
though, Myrinet uses 64/32 bit, 66/33 mhz PCI, where Dolphin uses 64/32
bit, 33 mhz only PCI, so I this would lead me to believe that Dolphin is
a lot closer to saturating their PCI interface, while Myrinet has and
can continue to improve their performance (not that this affects those
of us who already own Myrinet hardware).  Anyone have any experience or
comments.
-- 
Jared Hodge
Institute for Advanced Technology
The University of Texas at Austin
3925 W. Braker Lane, Suite 400
Austin, Texas 78759

Phone: 512-232-4460
FAX: 512-471-9096
Email: Jared_Hodge at iat.utexas.edu