Allocations of CPU's to projects

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Cruncher Pete
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#1 Allocations of CPU's to projects

Post by Cruncher Pete » Thu Aug 20, 2020 7:50 am

Up until now, I used the maximum number of CPU's to run one project on GPU and CPU. Sometimes I reduced the CPU to 1 less to allow the GPU a full CPU.

Now that I have full "Krunchie" capabilities thanks to David, I can see myself running a number of projects on instances or Multple Boincs but I need to reduce the cpu allocation to suit.

What is the best way of allocating a number of CPU threads for e.g to run 4 projects,. and to run 1 GPU?

I am asking this as I need to confirm my own theory of devided and conquer.
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davidBAM
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#2 Re: Allocations of CPU's to projects

Post by davidBAM » Sat Aug 22, 2020 4:55 am

Firstly, making the actual change is straightforward - simply set CPU count for each instance on the green menu. Krunchie will warn you if you have too many - or too few - threads in use across all instances on the machine concerned

Secondly, I don't think that is what you are asking :-) To answer "what is the optimum number of threads to allocate to each project in a mix of projects" would mean a very lengthy reply. Even then, I'm pretty sure I don't have all the answers as it is highly dependent on the hardware as well as the projects concerned.

It interests me greatly though as I've played around with several combinations looking for 'sweet' spots to best utilise resources such as RAM and L3 cache. There is also CPU affinity which I don't begin to understand despite @Bryan trying his best to explain to me.

I would encourage you to make a couple of lists with projects that are either 'undemanding' or 'demanding' where RAM is concerned as I've noticed that that what you bump into from time to time. Use the View WU Details on krunchie to report RAM usage on each WU (and total if you hover over column header)

Another point is that running half the thread count is not as daft as it seems. It means twice the amount of RAM per WU, twice the amount of L3 Cache per WU. Simply put, if 64 threads are taking an hour each to finish, then you might just find that 32 threads take less than half an hour each. NFS on Linux is definitely in this category for me (except on 3900X which have loads of L3 cache per thread)

Remember too that, outside of Sprints, it can make a lot of sense to work as a team by running projects to defend FB placings - thinking here of Gerasim of course, where your farm is really, really strong (all Windows, lots of threads)
I think this is fool-proof but could you just try it for me please? • There are 10 types of people in the world; those who understand binary, and those who don’t
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Cruncher Pete
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#3 Re: Allocations of CPU's to projects

Post by Cruncher Pete » Sat Aug 29, 2020 4:33 am

David in #2 of this forum gave an excellent explanation on this topic. Unfortunately, for one reason or another I wish I would have known that before I purchased a New Machine costing me over $6,000 but I retained the 32GBytes of RAM I already had.

As at this point in time we are pursuing a sprint in BoincFB. I managed to grab 250 WU's in the first hour and none thereafter since they are not producing any more. It called for a change of Tactics and I changed to TBrada only on all machines. This now will point out to those of you that Memory requirement is in deed very important. This new machine of mine has 64 cores and 128 threads Hyper threading.
Trying to run 128 threads resulted in a machine freeze, no mouse or keyboard activity. It woke me up, Memory. I changed the number of Cpus in cc-config in safe mode to 64 cores. The result was the same. Suspended waiting for memory. I halved it again and it confirmed that it will only run 32 WU's without needing extra memory.

You all know the cost of RAM and I am now not in the position to purchase more. 32GBytes is my maximum. Because of the greed of some projects, I will refuse to crunch their projects. The cost of helping them is getting more and more expensive. There has to be a limit. I will not be shy telling these projects what I think of their greed.

Hope that this thread will give insite to some of you that had not much experience in this field. Don't give up, find alternative. Keep on crunching and have a nice day.

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