I have a problem with BOINC that on my Fedora 20 systems, it ignores the CPU usage restriction in computing preferences (i.e. it runs even if a non-BOINC CPU usage is 700 %). On Fedora 19 everything is okay and BOINC computations are suspended when high CPU usage appears on the system. A weird thing is that on both Fedora 19 and Fedora 20 I have the same version of BOINC and the same kernel. Could anybody please suggest me any way how to debug the issue to find out what causes the difference? Thanks!

I assume you have a recent version of BOINC (7.2.x) running.

I backtracked the variable non_boinc_cpu_usage from the suspend reason in client/cs_prefs.cpp:250 to client/app.cpp:451
There a procinfo object is used to gather the information. So basically the function procinfo_setup in lib/procinfo_unix.cpp:173 (see line 224 for the logic) is gathering all the data.

There could be a problem accessing your /proc in Fedora 20 or there was a change from 19 to 20. But I guess that client/app.cpp line 454 is the cuplrit, but I didn't check further.

You could turn on the mem_usage_debug log flag on and look for "[mem_usage] non-BOINC CPU usage:" in the client log.