Hi Felix, just to give you an update on my progress so far. It took a while to find a case large enough to get significant differences between single and multiple cpu usage.
I used the tutorial from here[1]. I run ccx (compiled and packaged from the git-repo on alioth) with the following command for X threads. With X being 1, 2 and 4. export OMP_NUM_THREADS=X; /usr/bin/time -o TimingLog_CPUX.log -a ccx -i hook As I can see, everything runs as expected. I see additional threads in htop for each cpu. So for OMP_NUM_THREADS=2 i see 3 threads. But only, when the calculation is handed over to spooles. A few seconds after the output of "Using up to 4 cpu(s) for spooles." Also, the time required to complete the calculation decreases with more cpus in use. Approximately 4m for 1 cpu and 2m30.00s for a calculation with 4 cpus. > As you can see I tried with 2, but have done it with 4 and 6 as well. > The output messages and the messages in spooles.out change > accordingly, but the runtime and the cpu usage as reported by htop > remain the same. There is an option for htop, to list each thread process. You can turn this behavior on by pressing H or in the "Setup / Display options" menu, "Hide userland threads". Can you please test, whether switching this option on/off does change anything? Another question: How large is your case? Is it large enough, to get a significant difference between single and multiple cpu usage? The normal test cases shipped in the orig-tar of ccx normally are to small to get an improvement using more cpus. Hopefully the "solution" above helps. Notwithstanding the above I will dig a little deeper, maybe I missed something. Kind regards Wolfgang [1] http://www.libremechanics.com/
