Node Level Scaling on KNL (on Cori)
On this page, we track the state of node-level scaling on KNL (on Cori).
- Drop in parallel efficiency even for only 2 threads
- Runtime only decreases for ~30 threads, then it starts to increase again
- Level 5 results will be added soon which will also include idle rate measurements
The following image shows the runtime of the moving stars problem for different numbers of hpx threads ("-hpx:threads").
This corresponds to the parallel efficiency displayed in the next graph.
Console output to individual experiments can be found here.
The following command was used for the runs:
srun numactl -m 1 ./knl-build/octotiger-Release/octotiger \
-Disableoutput -Problem=moving_star -Max_level=${level} \
-Stopstep=0 --hpx:threads=${threads} \
--hpx:ini=hpx.stacks.small_size=0xC00000 -Ihpx.stacks.use_guard_pages=0 \
--hpx:print-bind --hpx:print-counter /threads{locality#*/total}/idle-rate \
> results/${name}_N${SLURM_NNODES}_t${threads}_l${level}_m1 2>&1