Gromacs or Tinkers?

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cansan
Posts: 127
Joined: Thu Oct 28, 2004 1:33 pm
Location: Germany

Gromacs or Tinkers?

Post by cansan » Tue Nov 30, 2004 4:30 pm

Hi all,

I have been folding for spcr for a few weeks with my humble 1.3 Athlon. When I started, it gave me a 854 gromac, which takes ages on my machine. Ok, more accurately it takes 7-8 days. These gave 155 points in about a week. Which I gather is really low...

Last week, when I had done about 2400/2500 of the same gromac, I had a power outage. When the electricity was back, it started not from ~2400 but from 0! I had the checkpointing frequency at 3 min! I don't understand why this happened? After that the same thing happened when I was at ~1000.

So, I got really angry and changed over to no deadline units. I thought this would give me less points but maybe smaller WUs. Guess what, yesterday and the day before I got two tinkers that were 49 and 42 points and finished in less than a day. Now that makes 45*7=315 PPW.

With gromacs: 155 PPW
With tinkers: ~300 PPW

I just don't understand this? Aren't the deadlineless units supposed to be less points? Any advice?

Putz
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Post by Putz » Tue Nov 30, 2004 5:39 pm

Athlons have an affinity for Tinkers, especially the earlier ones. However, my seat-of-the-pants opinion is that you should be getting way more than 155PPW out of your machine. My 1.6Ghz AthlonXP (2000+) usually gives me about that many points in two days on Gromacs work units.

cansan
Posts: 127
Joined: Thu Oct 28, 2004 1:33 pm
Location: Germany

Post by cansan » Tue Nov 30, 2004 5:42 pm

Does this have anything to do with the SSE stuff??

Or the "Disable highly optimized assembly code" option?

Tibors
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Post by Tibors » Tue Nov 30, 2004 8:36 pm

Yes, you get about twice as much points on Gromacs units if your processor can use SSE in stead of no optimisations. The difference between using 3Dnow and using SSE is less dramatic but still very noticable.

What happened to your Gromacs units is a known problem. When F@H writes a checkpoint it overwrites the previous one. When your system shuts down while it is writing a checkpoint, the checkpoint gets corrupted and the work has to start from the beginning. On the Folding-community forums it has been argued that this could be solved by using alternating checkpoints. But the F@H programmers have other things higher on their todo list.

If you set your checkpoint interval to 3 minutes the chance that the system is writing a checkpoint at the moment it shuts down is higher than with a checkpoint interval of 30 minutes.

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