Mark,
At 15:09 31.01.2008, Mark Hahn wrote:
I did not claim the opposite - I said that for small, cost-sensitive
clusters, it would be unusual to need IB's advantages (high bandwidth
and latency comparable to other non-Gb interconnects.)
in particular, I'm curious about the conventional wisdom
With more cores on a single node, the IB benefits are seen in much lower number
of nodes. I am testing some applications on a new cluster that I have (dual
sockets quad core Barcelona), and my first results are with Fluent new
benchmarks. I will have the numbers posted soon, so you all can
Brian Oborn wrote:
A quick side question. Is it possible to use IB as a cross-over with no
switch?
Yes, and the cables are the same.
If I had just 2 fat nodes could I connect the HCAs directly to
each other and avoid the switch costs?
Yes. With 3 nodes it might be cheaper
Brian Oborn wrote:
A quick side question. Is it possible to use IB as a cross-over with no
switch? If I had just 2 fat nodes could I connect the HCAs directly to
Yes.
each other and avoid the switch costs? Could this be extended to ring or
hypercube topologies?
Yeah ... but a switch
At 21:01 30.01.2008, Mark Hahn [EMAIL PROTECTED] wrote:
whenever I ask about IB bandwidth, people always point fingers
at weather codes, which apparently are fond of doing the transpose
in multi-dimension FFT's using all-to-all. while convenient, this
seems a bit silly, since transpose is O(N)
-Original Message-
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Håkon Bugge
Sent: 31 January 2008 09:51
To: Mark Hahn
Cc: Beowulf Mailing list
Subject: Re: [Beowulf] Cheap SDR IB
At 21:01 30.01.2008, Mark Hahn [EMAIL PROTECTED] wrote:
whenever I ask about IB bandwidth
whenever I ask about IB bandwidth, people always point fingers
at weather codes, which apparently are fond of doing the transpose
in multi-dimension FFT's using all-to-all. while convenient, this
seems a bit silly, since transpose is O(N) communications, not O(N^2).
Mark,
interconnect does
Mark Hahn wrote:
sure, and these are very fat nodes for which a fat interconnect is
appropriate for almost any workload that's not embarassing. but really
I wasn't suggesting that plain old Gb (bandwidth in particular) was
adequate for all possible clusters. I was questioning whether IB was a
With regard to weather codes. I looked at a program for
local forecasting. Just six or eight computational
nodes are used. The grid of physical data is not very dense
because the initial conditions do not have high spatial resolution.
The consequence is that each subdomain has alot of surface
Donnerstag, 31. Januar 2008, meintest Du:
SA On Jan 30, 2008, at 6:20 PM, Gilad Shainer wrote:
For BW, Lx provides ~1400MB/s, EX is ~1500MB/s and ConnectX
is
~1900MB/s
uni-directional on PCIe Gen2.
I thought the thrust of the original post was that you can
build now a cheap IB cluster with up to 24 nodes. The
subsequent discussion was around questioning whether you need
IB for up to 16-24 nodes.
The advantage you point to is for 32 nodes. There is no
question that IB is much
David Mathog wrote:
Joe Landman [EMAIL PROTECTED] wrote:
Gilad Shainer wrote:
IB for gaming? I have one ratio: 1e-1/3e-6.
that's human
reaction time versus IB latency.
Oh yes... I guess you did not play for a long
time. Did you? Talk
with someone who suffer from
Gilad Shainer wrote:
With more cores on a single node, the IB benefits are seen in much lower
number
of nodes. I am testing some applications on a new cluster that I have (dual
sockets quad core Barcelona), and my first results are with Fluent new
benchmarks. I will have the numbers
Richard Walsh wrote:
With more cores on a single node, the IB benefits are seen in much
lower number
of nodes. I am testing some applications on a new cluster that I have
(dual
sockets quad core Barcelona), and my first results are with Fluent
new
benchmarks. I will have the
With more cores on a single node, the IB benefits are seen in much
lower number of nodes. I am testing some applications on a new cluster
that I have (dual sockets quad core Barcelona), and my first results are
with Fluent new benchmarks. I will have the numbers posted soon, so you
all can
Just in case you've missed the announcements:
http://www.clustermonkey.net//content/view/222/1/
I'm always happy about new levels pricing agression, but I'm
a bit puzzled about for what kind of workloads this will matter.
whenever I ask about IB bandwidth, people always point fingers
at
Mark,
Thanks for being the knucklehead that allows me to respond to
you and a bunch of other knuckleheads :)
Just in case you've missed the announcements:
http://www.clustermonkey.net//content/view/222/1/
I'm always happy about new levels pricing agression, but I'm
a bit puzzled about for
On Jan 30, 2008 8:58 AM, Mark Hahn [EMAIL PROTECTED] wrote:
IB for gaming? I have one ratio: 1e-1/3e-6. that's human reaction
time versus IB latency.
Not to stray off-topic, but I must defend the needs of gamers. There are
e+6 pixels and the video card has to react to a very great deal,
Dear Mark,
Just in case you've missed the announcements:
http://www.clustermonkey.net//content/view/222/1/
I'm always happy about new levels pricing agression, but I'm
a bit puzzled about for what kind of workloads this will matter.
whenever I ask about IB bandwidth, people always
Gilad Shainer wrote:
IB for gaming? I have one ratio: 1e-1/3e-6. that's human
reaction time versus IB latency.
Oh yes... I guess you did not play for a long time. Did you? Talk
with someone who suffer from lagging and you will get the story, even
When he has a great video card. It's the
On Jan 30, 2008, at 6:20 PM, Gilad Shainer wrote:
For BW, Lx provides ~1400MB/s, EX is ~1500MB/s and ConnectX is
~1900MB/s
uni-directional on PCIe Gen2.
Feel free to contact me directly for more info.
Gilad.
My god, IB bandwidths always confuse me. :-)
I thought IB SDR was 10 GB/s signal
Just in case you've missed the announcements:
http://www.clustermonkey.net//content/view/222/1/
http://www.hpcwire.com/hpc/2073649.html
Enjoy!
Jeff
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