Hello, How could a user specify that he does not want to use hyper-threading in his jobscript?
We have a Cray XC40 system with 32 cores (64 threads) on each compute nodes (two Haswell sockets). The performance of some jobs varies between identical runs and we have found that this is due to threads allocation on the same core. We enabled task/affinity plugin and looked at cpu_bind option. We have found that the following does what we want: srun -n 32 --cpu_bind=map_cpu:0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31 ./app However, is there a shorter/nicer way of just "disabling" hyper-threading on a per-job basis? Maciej -- Maciej Olchowik HPC Systems Administrator KAUST Supercomputing Laboratory (KSL) Al Khawarizmi Bldg. (1) Room 0134 Thuwal, Kingdom of Saudi Arabia tel +966 12 808 0684 ________________________________ This message and its contents including attachments are intended solely for the original recipient. If you are not the intended recipient or have received this message in error, please notify me immediately and delete this message from your computer system. Any unauthorized use or distribution is prohibited. Please consider the environment before printing this email.
