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<div class="">Is there any documentation of the precise meaning of the bitmask that "--cpu-bind=verbose" reports? </div>
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<div class="">Also, can anyone explain why there's a difference between specifying "--ntasks" and "--cpus-per-task" in the #SBATCH header vs. in the srun command line, as my output below shows?</div>
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<div class="">If I use this sbatch header
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<div class="">#SBATCH --exclusive</div>
<div class="">#SBATCH --ntasks=8<br class="">
#SBATCH --cpus-per-task=8<br class="">
#SBATCH --hint=nomultithread</div>
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and "srun --cpu-bind=verbose" I get the following report:
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<div class="">cpu-bind=MASK - compute-7-16, task 0 0 [192319]: mask 0xff set<br class="">
cpu-bind=MASK - compute-7-16, task 1 1 [192320]: mask 0xff0000 set<br class="">
cpu-bind=MASK - compute-7-16, task 2 2 [192321]: mask 0xff00 set<br class="">
cpu-bind=MASK - compute-7-16, task 3 3 [192322]: mask 0xff000000 set<br class="">
cpu-bind=MASK - compute-7-17, task 4 0 [138387]: mask 0xff set<br class="">
cpu-bind=MASK - compute-7-17, task 5 1 [138388]: mask 0xff0000 set<br class="">
cpu-bind=MASK - compute-7-17, task 6 2 [138389]: mask 0xff00 set<br class="">
cpu-bind=MASK - compute-7-17, task 7 3 [138390]: mask 0xff000000 set<br class="">
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<div class="">but if I use</div>
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<div class="">#SBATCH --exclusive<br class="">
#SBATCH --ntasks=64<br class="">
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and "srun --ntasks=8 --cpus-per-task=8 --cpu-bind=verbose" I get
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<div class="">cpu-bind=MASK - compute-7-12, task 0 0 [8657]: mask 0xf0000000f set<br class="">
cpu-bind=MASK - compute-7-12, task 1 1 [8658]: mask 0xf0000000f0000 set<br class="">
cpu-bind=MASK - compute-7-12, task 2 2 [8659]: mask 0xf0000000f0 set<br class="">
cpu-bind=MASK - compute-7-12, task 3 3 [8660]: mask 0xf0000000f00000 set<br class="">
cpu-bind=MASK - compute-7-17, task 4 0 [139467]: mask 0xf0000000f set<br class="">
cpu-bind=MASK - compute-7-17, task 5 1 [139468]: mask 0xf0000000f0000 set<br class="">
cpu-bind=MASK - compute-7-17, task 6 2 [139469]: mask 0xf0000000f0 set<br class="">
cpu-bind=MASK - compute-7-17, task 7 3 [139470]: mask 0xf0000000f00000 set<br class="">
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<span class="Apple-tab-span" style="white-space: pre;"></span>thanks,</div>
<div class=""><span class="Apple-tab-span" style="white-space:pre"></span>Noam</div>
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