I'll try to provide more info if anybody needs it. Also, a second question, is it possible to set BOINC to use certain threads? As I want to use a program that only takes advantage of 3 CPU cores, specifically the first 3 cores, is it possible to let BOINC work on my other 5 threads? This is why I wanted to get into the manager in the first place.

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You might be asking the wrong question here. The Manager won't give you thread (or CPU core ID) level control, even if you get it running.

The best you can do is limit the total number of cores that BOINC is allowed to use, and let your other program pick the ones it wants first: BOINC will use whatever's left over, under OS control.

The manager would let you create a global_prefs_override.xml file using a GUI tool, but that's all it would do. You could create the file yourself, containing something like

<global_preferences>
   <max_ncpus_pct>62.5</max_ncpus_pct>
</global_preferences>

(to use five out of eight cores for BOINC)

Or - even more simply - you could make the same change via the global preferences page of any project your computer is attached to.

Or - even more simply - you could make the same change via the global preferences page of any project your computer is attached to.

Better do it there, else at the next contact with the project website, the value that the project sends out overwrites the manually edited value in the global_preferences.xml file.

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Thanks for the reply, since I posted the question I have been able to get into the manager, but unfortunately as you said I can't control specifically which threads BOINC can use, though at least it's good I can control how many. Maybe it might be a good feature to add in the future? I'm sure some of the more technical users would definitely appreciate it. Right now my PC is only doing projects from World Community Grid and I didn't see any options that would allow me to configure the specific threads BOINC could use. I wanted to make specifically use the other 5 threads because my application would probably cause BOINC to lower the work on all of the threads rather than just the ones I needed.

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Or - even more simply - you could make the same change via the global preferences page of any project your computer is attached to.

Better do it there, else at the next contact with the project website, the value that the project sends out overwrites the manually edited value in the global_preferences.xml file.

I have BOINC set to use local preferences, shouldn't this remove that issue?

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Or - even more simply - you could make the same change via the global preferences page of any project your computer is attached to.

Better do it there, else at the next contact with the project website, the value that the project sends out overwrites the manually edited value in the global_preferences.xml file.

I have BOINC set to use local preferences, shouldn't this remove that issue?

Yes, if you use the _override version of the file (the version that the manager, er, manages), that's persistent across project contacts.

Whereby I then of course wonder how you use the local preferences, if you cannot use the BOINC Manager. But on the other hand, if you know how to write the file contents, the global_prefs_override.xml file is easily made. ;-)

As for the actual problem of not being able to start the manager, I'll wait for a Linux guru to pass by, but suspect it's to do with:
- missing X server.
- permissions.

Which BOINC do you use?
And is it installed from repository, or from the BOINC website?

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Whereby I then of course wonder how you use the local preferences, if you cannot use the BOINC Manager. But on the other hand, if you know how to write the file contents, the global_prefs_override.xml file is easily made. ;-)

As for the actual problem of not being able to start the manager, I'll wait for a Linux guru to pass by, but suspect it's to do with:
- missing X server.
- permissions.

Which BOINC do you use?
And is it installed from repository, or from the BOINC website?

I already said that I was able to get into the BOINC manager since I asked the question, I presume because I forgot to quote you, you didn't receive a notification for it? Also it's installed from the website.

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Some things I should have added, and will add for the benefit of future readers:

One advantage of using the Manager GUI tool is that it issues an automatic 'Read local prefs file' after an edit, so the new setting takes effect immediately. If you create or edit the file at the command line, you have to issue a separate

boinccmd --read_global_prefs_override

(or wait until the next client restart) before they take effect.

One disadvantage of using the Manager GUI tool is that it creates a fully-populated override file, taking control of all web-editable values. My hypothesis in suggesting a single-entry override file was that web settings would remain in control for all other values. But that hypothesis is untested.

[The command-line approach seemed appropriate in this case because the OP seemed familiar with that mode of working]

Right now my PC is only doing projects from World Community Grid and I didn't see any options that would allow me to configure the specific threads BOINC could use. I wanted to make specifically use the other 5 threads because my application would probably cause BOINC to lower the work on all of the threads rather than just the ones I needed.

BOINC intentionally doesn't run tasks on specific cores. It just starts tasks and leaves it up to operating system to assign a core to the task. Distributing running programs to available cores is one of operating systems' jobs.

Just fixed my problem by using the command taskset (from utils-linux). I set BOINC to only use 5 cores then after finding out the processor IDs of the tasks BOINC was running, I was able to use taskset to make each task run on threads 3-7. Thank you for the information that the OS is the one that assigns the tasks to the cores and not the program itself. (as a side note, it seems like those threads are getting used
a bit more efficiently then when the tasks weren't assigned to any specific cores)

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