CPU support

hghocks
hghocks
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Topic 190075

How many CPUs are supported by the client? On a 16 CPU machine there are only 4 CPUs used. Is there a limitation?

Paul D. Buck
Paul D. Buck
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CPU support

Yes. And if I recall it is 4 CPUs.

You can TRY changing the preference setting "Use at most 'x' CPUs", but if I recall correctly, the BOINC Daemon itself has code that limits BOINC operations to 4 CPUs.

I do not recall the reason for the selection of the 4 CPU limit. But, you could ask on the developer's forum.

Personally, I do not see why there should be a limit. And, in the not too distant future we are going to be seeing more people running 8 and 16 CPU systems as workstations. Heck, a dual HT Xeon is running about $3K right now and I have 2 of them ... and looking at the dual dual-core PowerMac that just came out... those are all 4 CPU systems.

The next generation of dual core Xeons are in the pipe and there you have 8 with dual dual-core HT enabled processors ... of course, you can turn off HT, losing that 20% performance boost from HT ...

Walt Gribben
Walt Gribben
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The "Top Computers" stats

The "Top Computers" stats show a few with 8 processors and should work with 16 just fine.

If you're talking about this host, it shows 16 processors so BOINC recognizes all 16. It also shows zeros for floating point and integer speed. That could be messing up the scheduler calculations for determining how many workunits to send.

Check the messages for the benchmarks, if they aren't in the messages run them again and see if the results are valid. Try to run them when nothing else is running on the system (it'll suspend any workunits running at the time). That way you'll get accurate results.

[edit again]

I tried it with 10 CPU's, and after adjusting my preferences to 10 it started all 10. So BOINC doesn't appear to put a limit on the number of CPU's. THe scheduler doesn't either, it downloaded extra workunts to fill the quota

Walt

Keck_Komputers
Keck_Komputers
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Sorry Paul you made a slight

Sorry Paul you made a slight mistake here. There is no limit on the number of CPUs BOINC will run on. However there is a limit on either how many it will count when determining how much work to queue or on how many are figured into the total quota for that host. I forget which, however I lean towards it limiting the total quota.

BOINC WIKI

BOINCing since 2002/12/8

Paul D. Buck
Paul D. Buck
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THAT is it ... Ok ... Yes,

THAT is it ... Ok ...

Yes, so, for SAH you can get a maximum of 400 WU per computer ...

Now if we could get them to stop dividing the benchmark by the number of CPUs ... :)

Michael Roycraft
Michael Roycraft
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RE: Now if we could get

Message 18759 in response to message 18758

Quote:
Now if we could get them to stop dividing the benchmark by the number of CPUs ... :)

Is THAT the reason that Xeons, etc get shafted so badly on claim? I guess, looking at the arithmetic, what you say would pretty much explain that mystery.

Regards,

Michael

microcraft
"The arc of history is long, but it bends toward justice" - MLK

hghocks
hghocks
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Changing the preferences to

Changing the preferences to more CPUs solved my problem.

Thx
hg

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