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View Full Version : Folding@Home on multi-core/SMP boxes


werty316
07-08-2007, 07:52 PM
Looks quite interesting and I might just give it a try to see how fast the SMP client is.
We are also releasing another type of client: the Folding@Home SMP client. SMP means "Symmetric Multi-processing" and it is a term that generally refers to the situation where a computer has more than one processor core. Dual core CPU's are pretty common and even 4-core boxes (currently implemented as dual socket dual core computers, such as Apple's Mac Pro) are becoming common. With advances from Intel and AMD, quad core processors are on the horizon, with 8-core and even 16-core boxes soon to become common.

The goals of the SMP client and the GPU client are similar: in order to tackle many of the problems of interest (especially related to protein misfolding and aggregation, such as in Alzheimer's Disease), we need to not just have lots of computers participating, but we need results returned more quickly so that we can simulate trajectories of sufficient length. Right now, we achieve this by running for many months to years (indeed, our first Alzheimer's Disease simulations ran for almost two years straight). That's where the SMP and GPU (and PS3) clients come in. They give us considerably longer trajectories in the same wall clock time, allowing us to turn what used to take years to simulate even on FAH, to a few weeks to months.

Moreover, the SMP and GPU clients are complementary. The GPU client can greatly (~30x) speed up a specific type of calculation (implicit solvent calculations), whereas the SMP client can lead to a 4x speed up over the complete range of calculations we need to run. Even a 4x speed up is significant here, since it affects virtually all types of FAH calculations, turning a year's worth of work into a few months. As multi-core CPUs become more common, we expect this trend to become more and more important, especially as 8-core boxes (with dual 4-core CPUs) have already been announced.
http://folding.stanford.edu/FAQ-SMP.html

westy87
07-09-2007, 04:10 AM
Hmm might give this one a go, see what happens

Kougar
07-09-2007, 07:44 AM
Please note that their SMP client is still beta, and still buggy. For that reason they do not currently recommend it be used on dualcore only machines. Please use this only if you are willing to troubleshoot and report bugs and issues to Stanford. :)

KNOWN BUGS, COMPATIBILITY ISSUES, AND RUNNING NOTES

Please note that this is a beta release. While we have done lots of testing in house, there are limits to the bugs we can find in these limited tests (and hence the need for a beta test). Thus, we expect that there will be many problems with the client that need to be resolved. Below is a list of some of the relevant known issues or bugs for beta testers of this new client.

Known Bugs and issues

1) The core needs some time (often as much as 4 minutes) between work units to finalize work.

2)Printing to the log file sometimes gets weird due to multiple threads

3)The Linux client (and sometimes the OSX client) does not correctly detect RAM levels 2GB or greater. In this situation, please make sure to set the RAM by hand in the client configuration process (to reconfigure, run the client with the -configonly flag). If the memory is not read correctly, it defaults to a very low value. If your OSX client detects some huge amount of memory (eg 4294965248 MB), then you need to configure the RAM by hand with -configonly.

4)The core will print "No option -tpi" 4 times during the start up of the core

5)The core does not clean up its work files completely (can leave several files after the WU has completed)

Notes for running

1) We strongly suggest people run this client on 4-core boxes. While it will run on 2-core boxes, we have noticed some potential problems (we are looking into these issues now).

2)Most SMP WU's will be "big" WU's, so you'll have to configure the client that way. During the client configuration, when the client asks "Allow receipt of work assignments and return of work results greater than 5MB in size (such work units may have large memory demands) (no/yes)" say yes.

3)There is a brief pause (15-20 seconds) at the end of each WU. This is so we can make sure all the threads sync up. This is not a bug, as much as a limitation of SMP needing to synchronize the threads before moving on to the next WU.

4)The SMP core can get confused about disabling SSE, so we suggest running with the -forceasm flag if you notice that the SSE was disabled unnecessarily.

5)The linux client is a 32-bit executable, as we are planning on using a single client binary for SMP and non-SMP. However, this means that 64-bit linux distros will need to have 32-bit ELF support enabled.

westy87
07-09-2007, 01:35 PM
Ah alright. Im havin troubles at mmnt with one of my work units not sending results to the server. I had no net when it finished, then when net connected again it downloaded a new unit and started working on that but it keeps saying sending of unit failed or something, so yeh not sure how to fix that

Kougar
07-09-2007, 11:41 PM
If you are sure your net connection works fine then there is nothing you can do to fix it... It means the specific server you were assigned for that WU is not connectable... your client will eventually send the WU to a backup server after some set period of being unable to reach the originating server.

You might make sure you did not set the F@H program to not use Internet Explorer connectivity settings, this is disabled by default and should be left that way for most situations. :)

westy87
07-10-2007, 08:43 AM
So it needs to be set to use IE explorer settings?

Kougar
07-11-2007, 01:09 PM
No, it should NOT be set to use IE explorer connection settings.

westy87
07-12-2007, 08:04 AM
You might make sure you did not set the F@H program to not use Internet Explorer connectivity settings, this is disabled by default and should be left that way for most situations. :)

I was just makin sure cause of the double negative where you said to Not set F@H to Not use IE settings, but it's all good now thanks