I have run CactusTutorial.ipynb and obtained output for Hello World. However, when the characteristics of my computer (i9-7940X) were guessed, apparently something went wrong. I obtained the following output: Warning: Too many threads per process specified: specified num-threads=14 (ppn-used is 14)Warning: Total number of threads and number of threads per process are inconsistent: procs=1, num-threads=14 (procs*num-smt must be an integer multiple of num-threads)Warning: Total number of threads and number of cores per node are inconsistent: procs=1, ppn-used=14 (procs must be an integer multiple of ppn-used)+ set -e+ cd /home/robert/simulations/helloworld/output-0000-active+ echo Checking:+ pwd+ hostname+ date+ echo Environment:+ export CACTUS_NUM_PROCS=1+ export CACTUS_NUM_THREADS=14+ export GMON_OUT_PREFIX=gmon.out+ export OMP_NUM_THREADS=14 I can reduce the number of threads, but I'd rather not. I don't know enough yet about how this software works to set procs, though: it is not explicitly mentioned as such in the machine database. How would I do this?
Hello Robert,
does it actually abort? Symmetric multiprocessing is tricky to get right automatically and the automated CPU detection in simfactory that runs during setup-silent is designed to basically ignore them.
The HelloWorld code is very simple and does not make any attempt at getting it "right". As long as you get only "Warnings" there is nothing to worry about.
"Real" simulations usually use the "hwloc" and "SystemTopology" thorns which query the CPU and do a (much) better job at laying out threads onto physical cores and hardware threads. Codes in Cactus are typically of types where SMT gives only minimal benefit so is usually only worthwhile on big clusters and large production runs but not on workstations used for testing and debugging so the automated CPU detection code is simfactory does not handle it (or at least chooses to err on the side of caution).
Yours, Roland
I have run CactusTutorial.ipynb and obtained output for Hello World. However, when the characteristics of my computer (i9-7940X) were guessed, apparently something went wrong. I obtained the following output: Warning: Too many threads per process specified: specified num-threads=14 (ppn-used is 14)Warning: Total number of threads and number of threads per process are inconsistent: procs=1, num-threads=14 (procs*num-smt must be an integer multiple of num-threads)Warning: Total number of threads and number of cores per node are inconsistent: procs=1, ppn-used=14 (procs must be an integer multiple of ppn-used)+ set -e+ cd /home/robert/simulations/helloworld/output-0000-active+ echo Checking:+ pwd+ hostname+ date+ echo Environment:+ export CACTUS_NUM_PROCS=1+ export CACTUS_NUM_THREADS=14+ export GMON_OUT_PREFIX=gmon.out+ export OMP_NUM_THREADS=14 I can reduce the number of threads, but I'd rather not. I don't know enough yet about how this software works to set procs, though: it is not explicitly mentioned as such in the machine database. How would I do this?
Evidently the place to change the number of processes is here: %%bash# start simulation./simfactory/bin/sim create-submit tov_ET \ --parfile=par/tov_ET.par --procs=14 --num-threads=14 --walltime=0:20:0 At first I didn't see anything happening, but the CPU was getting hot (about 65C), so I suspected that something was going on, and was able to obtain the star plot. Perhaps I can now follow some of the erudite discussions in this forum. I also prefer to use Linux natively for such projects, as I did here (Ubuntu).
On Monday, October 19, 2020, 09:50:52 AM PDT, Roland Haas rhaas@illinois.edu wrote:
Hello Robert,
does it actually abort? Symmetric multiprocessing is tricky to get right automatically and the automated CPU detection in simfactory that runs during setup-silent is designed to basically ignore them.
The HelloWorld code is very simple and does not make any attempt at getting it "right". As long as you get only "Warnings" there is nothing to worry about.
"Real" simulations usually use the "hwloc" and "SystemTopology" thorns which query the CPU and do a (much) better job at laying out threads onto physical cores and hardware threads. Codes in Cactus are typically of types where SMT gives only minimal benefit so is usually only worthwhile on big clusters and large production runs but not on workstations used for testing and debugging so the automated CPU detection code is simfactory does not handle it (or at least chooses to err on the side of caution).
Yours, Roland
I have run CactusTutorial.ipynb and obtained output for Hello World. However, when the characteristics of my computer (i9-7940X) were guessed, apparently something went wrong. I obtained the following output: Warning: Too many threads per process specified: specified num-threads=14 (ppn-used is 14)Warning: Total number of threads and number of threads per process are inconsistent: procs=1, num-threads=14 (procs*num-smt must be an integer multiple of num-threads)Warning: Total number of threads and number of cores per node are inconsistent: procs=1, ppn-used=14 (procs must be an integer multiple of ppn-used)+ set -e+ cd /home/robert/simulations/helloworld/output-0000-active+ echo Checking:+ pwd+ hostname+ date+ echo Environment:+ export CACTUS_NUM_PROCS=1+ export CACTUS_NUM_THREADS=14+ export GMON_OUT_PREFIX=gmon.out+ export OMP_NUM_THREADS=14 I can reduce the number of threads, but I'd rather not. I don't know enough yet about how this software works to set procs, though: it is not explicitly mentioned as such in the machine database. How would I do this?
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