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Switching power "can cause some work units to fail"?

Posted: Sun Apr 19, 2020 10:08 pm
by BP2020
I set folding@home "while I'm working" and power to "medium". It uses 3 cores. Sometimes I'll move away from the PC for some time and I'll set the power to "high" in the middle of a work unit which uses 4 cores on my PC. And then when I come back I'll do this in reverse. This generates warnings in the log:

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WARNING:WU01:FS00:Changed SMP threads from 3 to 4 this can cause some work units to fail
WARNING:WU01:FS00:Changed SMP threads from 4 to 3 this can cause some work units to fail
Is that bad? Do I know that my work unit has failed in the end i.e. would the log indicate that in some way after the work unit has been 100% completed?
Also, can I extrapolate from not getting all the estimated points shown in the web dashboard that my work unit has failed in some way or something like that?

I don't care about points, I'm just concerned about not helping as much as I can and ruining my work unit by switching power like I do. Would it be better to just set this to "medium" all the time and never change it?

Thank you for any assistance.

Re: Switching power "can cause some work units to fail"?

Posted: Sun Apr 19, 2020 10:54 pm
by kiore
They would fail if you had a work unit that only worked on x cores and you reduced to x-1. I think this unlikely to be an issue on everyday CPU's but could do so if using a cpu with large numbers of cores which these days would be more than 8 and probably higher than that. If your unit crashes and sometimes they do you would just see a new unit appear I think, but if you want to monitor it more closely use the advanced view which would show you a log indicating the reason for the crash or failure. I you are using a quad core laptop for example I wouldn't worry.

Re: Switching power "can cause some work units to fail"?

Posted: Mon Apr 20, 2020 5:23 am
by BP2020
Thank you! Well the warnings text I posted came from the log in the advanced view indeed and I haven't seen anything in the log about fail or dumping except these warnings. But just to be on the safe side, once I did x+1 (high), I won't do x-1 (medium) for the duration of the work unit i.e. until it gets completed... I wish I had a better rig. Not offended you might have thought that's a laptop :), actually it's a desktop but it's not the latest. In any case, thanks again for your help!

Re: Switching power "can cause some work units to fail"?

Posted: Tue Apr 21, 2020 2:33 am
by PantherX
Out of curiosity, what's the use-case for changing CPU folding from Medium to High?

Generally speaking, the priority of CPU folding is a low one so virtually all other normal tasks are at a higher priority. Thus, you may not notice any impact while using those applications and can continue to fold in the background without thinking about it :)

Re: Switching power "can cause some work units to fail"?

Posted: Wed Apr 22, 2020 5:37 am
by BP2020
Thank you for explaining this! I did check in the task manager and it's low priority indeed, it's not very demanding for sure as my rig is really not the latest (i5-2500k) and I'm using the computer normally to do the stuff I usually do. But still folding :) Also I've noticed I got assigned a significantly longer CPU WU this time around (14588 (0, 47, 37)), it's been running all day... As for my GPU, I don't have to wait too too long to get a WU, some few hours at most as opposed to what others have experienced. But this is off topic. Thanks again!

Re: Switching power "can cause some work units to fail"?

Posted: Wed Apr 22, 2020 6:51 am
by bruce
WUs come in all sizes and previous attempts to customize the assignment to the speed of the hardware have generally been unsuccessful.

As far as CPU folding is concerned I don't see any reason not to fold those WUs at FULL since it really doesn't interfere with foreground activities. (GPU assignments are another matter, but that wasn't your question.)

the messages about changing between small numbers of threads like 3 to 4 causing some work units to fail should be ignored. There are, certain larger numbers where something can happen but it wasn't well understood when that warning was added.