[Beowulf] Intel buys QLogic InfiniBand business

Bill Broadley bill at cse.ucdavis.edu
Fri Jan 27 21:10:02 EST 2012


On 01/27/2012 02:25 PM, Gilad Shainer wrote:
> So I wonder why multiple OEMs decided to use Mellanox for on-board 
> solutions and no one used the QLogic silicon...

That's a strange argument.

What does Intel want?  Something to make them more money.

In the past that's been integrating functionality into their CPU or
support chipsets.  In the past that's been sata, usb, memory controller,
pci-e controller, and GigE.  The cost in transistors and die
area seems very relevant to Intel's interests.

Anyone have an estimate on how much latency a direct connect to QPI
would save vs pci-e?

What to motherboard board manufacturers want?  Something to make them
more money.

So that's mostly marketing/reputation, pricing, and whatever they can do
to differentiate themselves.  If buying a $150 IB chip lets them charge
$400 more then it's a win, assuming they spend less than $250 of R&D to
add it to the motherboard.  I doubt the difference in transistors or a
few watts would be a big deal either way.

>> Also, keep in mind that Intel's benchmarking group in Moscow has a 
>> lot of experience with benchmarking real apps for bids using 
>> TrueScale
head-to-head
>> against other HCAs, and I wouldn't be surprised if it was the case
that TrueScale
>> QDR is faster than that other company's FDR on many real codes,
> 
> 
> Surprise surprise... this is no more than FUD. If you have real
> numbers to back it up please send. If it was so great, how come more
> people decided to use the Mellanox solutions? If QLogic was doing so
> great with their solution, I would guess they would not be selling the
> IB business...

FUD = Fear, Uncertainty, and Doubt.  Doesn't sound like FUD to me.
More like a cheap attack on Greg, I think we (the mailing list) can do
better.

I've personally compared several generations of Myrinet and Infinipath
to allegedly faster Mellanox adapters.  Mellanox hasn't won yet, but
I've not compared QDR or FDR yet.  With that said the reason I run the
benchmarks to find the best solution and it might well be Mellanox next
time.  It would be irresponsible to recommend Mellanox cluster provide
just pick mellanox FDR over Qlogic QDR just because of the spec sheet.
Of course recommending Qlogic over Mellanox without quantifying real
world performance would be just as irresponsible.

Maybe we could have a few less attacks, complaining and hand waving and
more useful information?  IMO Greg never came across as a commercial
(which beowulf list isn't an appropriate place for), but does regularly
contribute useful info.  Arguing market share as proof of performance
superiority is just silly.

Speaking of which, you said:
  There is some add latency due to the 66/64 new encoding, but overall
  latency is lower than QDR. MPI is below 1us.

I googled for additional information, looked around the Mellanox
website, and couldn't find anything.  Is that above number relevant to
HPC folks running clusters?  Does it involve a switch?   If not
realistic are there any realistic numbers available?
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