[Beowulf] [landman at scalableinformatics.com: Re: [Bioclusters] FPGA in bioinformatics clusters (again?)]

[Eugen Leitl]

----- Forwarded message from Joe Landman <landman at scalableinformatics.com> -----

From: Joe Landman <landman at scalableinformatics.com>
Date: Sat, 14 Jan 2006 11:45:14 -0500
To: "Clustering,  compute farming & distributed computing in life science informatics" <bioclusters at bioinformatics.org>
Subject: Re: [Bioclusters] FPGA in bioinformatics clusters (again?)
User-Agent: Thunderbird 1.5 (Windows/20051201)
Reply-To: "Clustering,  compute farming & distributed computing in life science informatics" <bioclusters at bioinformatics.org>

[in order to keep this list of a higher quality, lets keep the marketing 
side to a minimum, and simply debate the merits]

Kathleen wrote:

>>From what I'm learning, cross communication is less likely an issue in
>transactional-based problems.  Protein-folding would be a great example of a
>non-transactional problem that is tightly coupled (needs cross

???

Protein folding, depending upon the algorithm used, could be expressed 
in terms of a lattice model, a force field model with or without 
electrostatics and rigid atoms, or more complex models with 
electrostatics and quantum effects, etc.  The computational cost of 
these models vary tremendously.  If you are attempting to do a 
conformational search over a large molecule, you really want to set up a 
huge sample and search space.  This is a embarrassingly parallel 
problem.  Not tightly coupled.  Very little in-algorithm communication. 
 Most of it is done in terms of sending information back to the main 
process.

[ ... the rest of the marketing bits deleted ...]

>Can a user intermix FPGAs with COTS-based technology 

Yes.  Easily.  This is being done today.

>What if one FPGA on a board fails? 

Buy a new one.  They are around the same price as a node or two.  Most 
are covered by a warranty of some sort.

>How easy
>is it to swap that out?  

One version:  pop the top of the unit off, pull the card out, put the 
new one in, pop the top back on, reboot.

Another version:  disconnect the USB2 cable and connect the new one.

Another version:  disconnect the network wire/optical cable and connect 
the new one

...

>Do you swap out just the failed FPGA or the whole
>board? 

Same debugging model as the node.  FPGAs don't tend to go bad 
individually.  You will debug it at the same level as the node (e.g. the 
subsystem).  I don't see people pulling off the northbridge from their 
motherboards when it fails.  I see them replacing the motherboard.  This 
is no different.

>Who would swap that out? 

Anyone who knows how to put cards into their machine.  This includes the 
vast majority of people on this list, or those who consume clusters in 
general.

>What happens to the work allocated to the
>failed FPGA, 

This is up to the scheduling software.  If configured as such, this is 
not a problem.  It is identical to the issue of what happens when a node 
fails, as the FPGA is part of the node.

>does it get dynamically re-directed? What is the max # of FPGAs
>for a single board and does each board cross communicate?    

Given that a single FPGA is 100x (one hundred times) faster on pairwise 
sequence alignment than the host CPU, how many FPGA's do you think you 
need?  Similarly, other codes are anywhere from 10x to 100x the 
performance of a single node.  The cost for this performance is 
excellent.  As volumes increase, the cost gets even better.

The correct model for looking at FPGAs or any other coprocessor in 
machines is to consider them to be just like a video card.  Most people 
on this list (or using a cluster) would have no trouble dealing with a 
defunct video card, and they are not going to pull off the GPU if it 
fails.  Moreover, the video card is 10-100x faster at rendering OpenGL 
graphics than the host processor.  Again, the cost for this performance 
is excellent.

Even more importantly, this model, the attached processor, is well 
established in the PC/server industry.  We (HPC and cluster users 
collectively) have attached processors of all sorts: Graphics, RAID, 
SCSI, SATA, Network, low latency network (Infinipath, Infiniband, 
Myrinet), ...  and a long history of leveraging the highest performing 
and best price performance systems.  I don't see attached processing 
replacing clusters or HPC systems, I see it augmenting them, in much the 
same way that we see RAID cards augmenting IO, or graphics cards 
augmenting displays.  The people who need and care about performance 
will likely be interested in these systems.

-- 
Joseph Landman, Ph.D
Founder and CEO
Scalable Informatics LLC,
email: landman at scalableinformatics.com
web  : http://www.scalableinformatics.com
phone: +1 734 786 8423
fax  : +1 734 786 8452
cell : +1 734 612 4615

_______________________________________________
Bioclusters maillist  -  Bioclusters at bioinformatics.org
https://bioinformatics.org/mailman/listinfo/bioclusters

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Eugen* Leitl <a href="http://leitl.org">leitl</a> http://leitl.org
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