SMP Client Questions

[ChrissyT88]

Bit of history - i have not been folding long, but have been running the GPU client and 2 5.91 console clients on an overclocked Q6600 for a couple of weeks (not folding 24/7). The gpu gives a good points output, but i have become increasingly aware that the console clients are not making the most of the quad (mainly due to the huge output by others!).

I set up the smp client this evening to give it a go and see how well it will run. The install was a it of a pain, bit i got it working. To begin with i forgot to add the -smp flag and the -local flag, and the client dutifully got a regular (non smp) gromacs work unit and began work. I closed the client and restarted using the SMP client and its crunching away an the smp-gromacs core. However, i do have a few questions:

1. I presume that since i added the -smp flag and it downloaded an smp WU that the other, non smp gromacs unit is gone?

2. Im not sure that i will be able to run the smp client in the long run. This PC is not on 24/7, and im not sure that its work rate will be sufficient to achieve the deadlines. However, the non smp gromacs WU that it picked up has a nice long deadline and carries more points than the WUs from the normal console client. Is it possible to use the SMP client to only fetch 'regular' work units? If so, can these units address more than one core, or are they limited as with the normal console clients?

3. What actually happens if you miss a deadline?

Cheers

 

[MikeTimbers]

How long per day do you leave it on? You should use something like FAHmon or FAHspy to determine the throughput per hour and then see how many hours per day it would need to be on to return in time then see if you can manage that. As someone who never willingly turns a client off, I simply can't understand the whole turning off thing.

 

[ChrissyT88]

At the moment its on quite a bit - id say about 8 hours a day. Im going to leave it on a little longer over the next few days to try and make some progress, but that wont be sustainable. I would love to leave it on 24/7, but the computer would stop me sleeping, and i cant really justify the leccy costs. Using FAHmon, i would be pushing the limits of the deadline. Im confident it will make it this time, but a shorter deadline... i wouldnt be so sure. In a month or so i begin the final year of my degree, so the PC will probably be on less (+ need to save money on electricity as a student!). I would love to know if you can run the SMP client to recieve only non smp WUs - these seem to compute quicker and give more points than running the standard 5.91 console client.

 

[Mattus]

I would love to know if you can run the SMP client to recieve only non smp WUs - these seem to compute quicker and give more points than running the standard 5.91 console client.

The client is a 'unified client'. In other words, there's only one client - when run in SMP mode it fetches SMP WUs, and when run in normal mode it fetches normal WUs (the same WUs that the old 5.91 would get). There's no advantage to running the SMP client in normal mode over running the old client - you've probably just been lucky. The normal units that the SMP picks up can only use one core.

I presume that since i added the -smp flag and it downloaded an smp WU that the other, non smp gromacs unit is gone?

Sounds like you've got rid of it, yeah.

What actually happens if you miss a deadline?

Not much. Each WU actually has two deadlines - the 'preferred deadline' and the 'final deadline'. 'Preferred' is when Stanford really want the WU back by. If you submit a completed WU after the preferred deadline BUT before the final deadline, the WU will already have been re-issued to someone else (when the preferred deadline expires) BUT you'll still get points for it. WUs returned after the final deadline don't earn any points at all, and if you start a client with a WU that's passed the final deadline, it will detect this and delete the WU.

In other words: missing preferred deadlines is borderline OK, missing final deadlines will waste your computing time and leccy

 

[ChrissyT88]

Cheers Mattus - i did not realise it was a unified client. I think i will run the client picking up normal WUs and switch to SMP when i know i will have the time. Thanks for the info on the dealines - its good to know nothing too bad will happen! Thanks again.