headers
Heiko Bauke | 1 Mar 2011 14:30
Picon

Re: Random numbers (was Re: /dev/random entropy on stateless/headless nodes)

Hi,

On Mon, 28 Feb 2011 15:03:33 -0500 (EST)
"Robert G. Brown" <rgb <at> phy.duke.edu> wrote:

> It would also be very interesting to try feeding one of your MRG or
> YARN-type generators into dieharder and running the full series of
> tests on it (there are actually several diehard tests in dieharder
> that look for hyperplanar correlations as well as the long tail
> "monkey" tests). If I ever have time I'll try to give it a shot.  Is
> the library and/or a cli available anyplace easy to find?

there is an open source C++ library implementing our YARN generators and
others, see http://trng.berlios.de/ and http://trng.berlios.de/trng.pdf .

	Heiko

--

-- 
-- Irrend lernt man.
-- (Johann Wolfgang von Goethe, 1749-1832)
-- Number Crunch Blog  <at>  http://numbercrunch.de
--        Heiko Bauke  <at>  http://www.mpi-hd.mpg.de/personalhomes/bauke
Permalink | Reply | 2 comments |
headers
Robert G. Brown | 1 Mar 2011 16:25
Gravatar

Re: Random numbers (was Re: /dev/random entropy on stateless/headless nodes)

On Tue, 1 Mar 2011, Heiko Bauke wrote:

> Hi,
>
> On Mon, 28 Feb 2011 15:03:33 -0500 (EST)
> "Robert G. Brown" <rgb <at> phy.duke.edu> wrote:
>
>> It would also be very interesting to try feeding one of your MRG or
>> YARN-type generators into dieharder and running the full series of
>> tests on it (there are actually several diehard tests in dieharder
>> that look for hyperplanar correlations as well as the long tail
>> "monkey" tests). If I ever have time I'll try to give it a shot.  Is
>> the library and/or a cli available anyplace easy to find?
>
> there is an open source C++ library implementing our YARN generators and
> others, see http://trng.berlios.de/ and http://trng.berlios.de/trng.pdf .

Thanks, I grabbed it.  I don't usually use C++, but hopefully I can link
this back to a C interface or at worst write a simple CLI program to
spit out a binary stream.  dieharder can test a binary stream via a pipe
(it is set up to test "large" numbers of random numbers, much larger
than diehard, although practically speaking many of the tests are
asymtotic and fail if you try to test the 10^12 and up numbers of rands
used in many modern MC computations.  But it at least makes it easy (and
still fairly reliable) to test 10^9 or more.  (I'd love to make it work
for longer streams, but that proves to be remarkably difficult for
numerical reasons, for at least the most "interesting" tests...:-).

Might take a while to get around to this, but if/when I do I'll try to
let you know.
(Continue reading)

Permalink | Reply | 1 comment |
headers
Hearns, John | 1 Mar 2011 16:50
Favicon

Why do we need SANs

This is a thought provoking article on storage:

http://www.theregister.co.uk/2011/03/01/why_do_we_need_sans/

In the light of the recent thread on Thunderbolt, note:
"Infiniband or ..... extermalised PCIe bus"
Do we see the HPC system of the future being a huge blade server farm,
running lots of virtual machines,
with some sort of object storage system spread across the machine
running on selected blades?

John Hearns | CFD Hardware Specialist | McLaren Racing Limited
McLaren Technology Centre, Chertsey Road, Woking, Surrey GU21 4YH, UK

T:  +44 (0) 1483 261000
D:  +44 (0) 1483 262352
F:  +44 (0) 1483 261010
E:  john.hearns <at> mclaren.com
W:  www.mclaren.com

The contents of this email are confidential and for the exclusive use of the intended recipient.  If you
receive this email in error you should not copy it, retransmit it, use it or disclose its contents but
should return it to the sender immediately and delete your copy.
Permalink | Reply | 1 comment |
headers
Hearns, John | 2 Mar 2011 10:44
Favicon

Re: Random numbers (was Re: /dev/random entropy on stateless/headless nodes)

Talking about seeding random numbers from dates and network interfaces,
I happen to be looking at the Intel igb driver for a completely separate
reason today.

One of the parameters in the igb kernel module is:

parm:           entropy:Allow igb to populate the /dev/random entropy
pool (int)

I guess this isn't news to most people.
John Hearns

The contents of this email are confidential and for the exclusive use of the intended recipient.  If you
receive this email in error you should not copy it, retransmit it, use it or disclose its contents but
should return it to the sender immediately and delete your copy.
Permalink | Reply | 0 comments |
headers
Mark Hahn | 4 Mar 2011 06:15
Picon
Picon
Favicon

Re: Why do we need SANs

> This is a thought provoking article on storage:
>
> http://www.theregister.co.uk/2011/03/01/why_do_we_need_sans/

I didn't think it was particularly good: basically just the observation
that you can put lots of servers instances into a big box and do away 
with a lot of infrastructure.  call it "mainframe".

the reason this is not good and maybe even bad is that it pretends 
that there's no need for scalable systems.  and it seems to be based 
on the premise that infrastructure such as FC, which has always been
very complex and expensive, would somehow be necessary.

besides, who would even propose SANs these days?  they're inherently
hostile to sharing, and it's all about sharing today...

> In the light of the recent thread on Thunderbolt, note:
> "Infiniband or ..... extermalised PCIe bus"

as far as I can tell, thunderbolt doesn't introduce anything interesting
regarding addressing, switching fabrics or low-latency transactions between
hosts.  I can't tell whether Intel wants to push it in that direction,
or whether it's a short-term sop for Apple.

> Do we see the HPC system of the future being a huge blade server farm,
> running lots of virtual machines,

hell no.  first of all, blades are done.  they never made much sense,
and what little sense they had (higher efficiency PSUs and cooling)
has now become available in standard/commodity parts.
(Continue reading)

Permalink | Reply | 0 comments |
headers
Mark Hahn | 8 Mar 2011 06:26
Picon
Picon
Favicon

Re: Execution time measurements (fwd)

Hi list,
I'm forwarding a message (took the liberty of inserting some of my own
comments...)

Mikhail Kuzminsky writes:
> I still don't have the possibility to send the messages directly to Beowulf
>maillist (although I receive all the mail messages). Could you pls forward
>my question to beowulf <at> beowulf.org ? 
>
> Thanks for your help !
> Mikhail
>
> Execution time measurements
>
> I  obtained strange results for Gaussian-09 (G09) execution times in
>sequential (!) run on dual socket Opteron-2350 based node under Open SuSE
>10.3 (kernel 2.6.22). The measurements were performed for  "pure cpu-bound"
>job (frequencies calculation at DFT level) where start-stop execution time
>is practically equal to cpu execution time (difference is lower than 1 min
>per 1 day of execution). G09 itself prints both cpu execution time, and
>start & stop dates/time information. 
>
> There is some job which execution time is about 1 day. But really it was
>measured two *DIFFERENT* execution times: 1st - 1 day (24h) and 2nd - 1 day
>3 hours (27h). Both results were reproduced few times and gives the same
>quantum-chemical results excluding execution time.  There was no other
>applications run simultaneously w/this measurements. Execution time
>difference isn't localized in any of G09 parts (links).

OK, if I understand: same tests, different timings.
(Continue reading)

Permalink | Reply | 19 comments |
headers
Douglas Eadline | 9 Mar 2011 16:48
Favicon

Chinese supercomputers to use ‘homemade’ chips


Interesting:

Chinese supercomputers to use ‘homemade’ chips

http://timesofindia.indiatimes.com/tech/personal-tech/computing/Chinese-supercomputers-to-use-homemade-chips/articleshow/7655183.cms

--
Doug

--

-- 
This message has been scanned for viruses and
dangerous content by MailScanner, and is
believed to be clean.
Permalink | Reply | 17 comments |
headers
Paul Van Allsburg | 10 Mar 2011 17:49
Picon
Favicon

ramdisk with tmpfs

Hi All,
I want to make a ramdisk available to cluster users and I'm curious what  your experiences/suggestions
might be.  I'm adding 40 
machines to a cluster that have 24 gig of ram.  I'd like to offer the option of allowing some users to be able to
run a job on a 
machine with 20 gig carved out for a ram disk.

The cluster is running centos 5.5 with torque & maui.

I expect the user will have to request one machine for the job and have the prologue/eplogue scripts mount &
unmount the 
ramdisk. Are there any success / horror stories that I might be enlightened by?

Thanks!
Paul

--

-- 
Paul Van Allsburg
Scientific Computing Specialist
Natural Sciences Division, Hope College
35 E. 12th St.  Holland, Michigan 49423
616-395-7292    vanallsburg <at> hope.edu
http://www.hope.edu/academic/csm/
Permalink | Reply | 3 comments |
headers
Craig Tierney | 10 Mar 2011 18:16
Picon
Favicon

Re: ramdisk with tmpfs

On 3/10/11 9:49 AM, Paul Van Allsburg wrote:
> Hi All,
> I want to make a ramdisk available to cluster users and I'm curious what  your experiences/suggestions
might be.  I'm adding 40
> machines to a cluster that have 24 gig of ram.  I'd like to offer the option of allowing some users to be able to
run a job on a
> machine with 20 gig carved out for a ram disk.
>
> The cluster is running centos 5.5 with torque&  maui.
>
> I expect the user will have to request one machine for the job and have the prologue/eplogue scripts mount& 
unmount the
> ramdisk. Are there any success / horror stories that I might be enlightened by?
>
> Thanks!
> Paul
>

As far as I recall, Centos creates a ramdisk by default at /dev/shm whose
maximum size is 1/2 of available memory.  The ramdisk uses available memory
as needed, and doesn't block an application from allocating
all of memory (as long as there is nothing in the ramdisk).

So you don't have to create one.  You can leave it bigger if you want,
but what is important is that the prologue/epilogue clears out the files
left there before the next run.  You could just mount/umount one as well
if you want, as you can have multiple ramdisks mounted at one time which
all size dynamically.

Craig
(Continue reading)

Permalink | Reply | 2 comments |
headers
Karen Shaeffer | 11 Mar 2011 00:23

Re: IBM's Watson on Jeopardy tonight

On Wed, Feb 16, 2011 at 01:06:35PM -0500, Robert G. Brown wrote:
> On Wed, 16 Feb 2011, "C. Bergström" wrote:
> 
> >>We are, but that problem is, well, "hard".  As in grand challenge hard.
> >I wonder how you'd really describe the human brain learning in terms of a 
> >programming model....
> 
> Well, AI researchers tend to have two answers.  One is semantic and the
> other is microscopic.  The semantic description is
> functional/operational, broken down in terms of e.g. conditionals and
> logical elements, and doesn't come close to explaining consciousness
> (see Searle's "Chinese Room" objection):
> 

Hi,
Well, IBM is presenting "Inside the mind of Watson" at Stanford University
on March 14. The speaker is Chris Welty of IBM. There are actually several
presentations. Here is one:

http://bmir.stanford.edu/events/view.php/inside_the_mind_of_watson

There is another one at 12:15 PM earlier that day associated with the
symbolic systems group. Those are often open to the public, if you
ask for permission to attend.

Karen
--

-- 
 Karen Shaeffer
 Neuralscape, Palo Alto, Ca. 94306
 shaeffer <at> neuralscape.com  http://www.neuralscape.com
(Continue reading)

Permalink | Reply | 1 comment |

Gmane