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-   -   Prime95 a multi-threaded application? (https://www.mersenneforum.org/showthread.php?t=2627)

Unregistered 2004-06-10 19:40

Prime95 a multi-threaded application?
 
I have 4 Intel SRPL8 servers clustered. Each server has 8 Intel Pentium III Xeon 900Mhz procs. As an example, on each server I am able to run 8 separate instances of Seti@Home’s text based client to make full use of all 8 procs. Can I do this with Prime95 and if so how?

Prime Monster 2004-06-10 19:59

[QUOTE=Unregistered]I have 4 Intel SRPL8 servers clustered. Each server has 8 Intel Pentium III Xeon 900Mhz procs. As an example, on each server I am able to run 8 separate instances of Seti@Home’s text based client to make full use of all 8 procs. Can I do this with Prime95 and if so how?[/QUOTE]
There are two ways in which you can do this, AFAIK :smile:. The first is running multiple copies of the prime95 client (single-threaded) and start the client with parameters telling it that more than one copy is running. ( -A0, -A1,,,-A7). The clients need to be started from the cmd line (assuming you are running windows). In this case you are testing 8 exponents simultanously on each machine.

The second way is to run Glucas, a multithreaded mersenne application. In this case you are testing 1 exponent at a time on each machine.

PM

delta_t 2004-06-10 21:22

If you have these running Linux or FreeBSD, the command line for each processor would be ./mprime -Ax -b
Where -Ax would be the processor # (-A0, -A1, -A2, . . .). The -b is for background running.
If these are Windows, then there is a processor affinity setting in Prime95.
I also think that mlucas may have just become multi-threaded just like glucas?

Unregistered 2004-06-10 21:58

Thanks!

delta_t 2004-06-10 22:28

Oh yeah. First remember to run without the -b so you will get asked all the appropriate questions about account name, etc. You could also just do ./mprime -Ax -m to call up the menu to make any changes necessary.

Unregistered 2004-06-10 22:32

I am using Win2k AS sp4. Is this OS compatible with mlucas and glucas? If so, where do I obtain these two apps?

delta_t 2004-06-10 23:02

Windows server, you may be out of luck with glucas or mlucas. They are mostly for other OS and processors. But if you are still interested [url]http://glucas.sourceforge.net/[/url] and [url]http://www.hogranch.com/mayer/README.html[/url]
I believe Guillermo and Ernst used their multi-threaded versions for M41 verication on Itanium 2's.
Prime95 is really great for x86 processors, and easy to use on Windows platform. In your case you'd probably want to run one case for each processor. However with that said, search the hardware forum for discussions on multi-CPU machines running multiple instances of Prime95. You may not want to run all LL-tests on each processor due to performance issues with memory contention.

Unregistered 2004-06-10 23:09

I have a gig of RAM in each machine. That should be adequate I would think???

delta_t 2004-06-10 23:17

It's not the amount really, but the speed between the RAM and processor. As an example I have a dual processor Athlon 1.2G with PC2100 RAM and when I run two instances of LL there is a slow down in both due to the fact that both are competing with each other for the RAM. My dual Xenon 2.4G has dual channel DDR333 and I see no slow down because the dual channel RAM is much faster so I am able to run 2 instances of LL tests with minimal speed degration. Actually on the dual Athlon I run 1 instance of LL, and 1 instance of trial factoring. That is because the trial factoring isn't RAM intensive because it does everything in L2. You should try some different combos and see for yourself. There is a benchmarking feature built into Prime95. Also, check out the Perpetual Benchmark thread and see what kind of performance people are getting. [url]http://www.mersenneforum.org/showthread.php?t=59[/url]

delta_t 2004-06-10 23:22

Look here as well [url]http://www.mersenneforum.org/showthread.php?t=2398&highlight=dual+processor[/url]
Here are some benchmarks on multiple instances [url]http://www.mersenneforum.org/showpost.php?p=18990&postcount=97[/url]
You'll see in the above thread that two instances of LL slow things down while 1 LL and 1 TF do not. Running the benchmark with an LL is just like running 2 LL tests.
However you said yours was an 8-way so you should test it out for sure. You may have a better bus than with the dual processor machines listed.
Here may help you in setting up multiple instances:
[url]http://www.mersenneforum.org/showthread.php?t=1859&highlight=dual+processor[/url]

T.Rex 2004-06-11 05:31

GLucas : for Unix
 
Yes, GLucas is dedicated to Unix system.
About the link: [url]http://glucas.sourceforge.net/[/url] , its contents is out of date. Guillermo is facing problems to update it, though he has recently improved the software for multi-threading and he has fixed several problems.
He said that he plans to provide the last version soon, I think.
Tony


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