Hello everyone,
I have a Dell Precision Tower 7910 with the Dual Intel® Xeon® Processor E5-2697 v4 (18C, 2.3GHz, 3.6GHz Turbo, 2400MHz, 45MB, 145W). I use it to run various programs written in MPI Fortran. The processor has 36 physical cores, but because of the hyperthreading technology, the system shows 72 CPUs.
I've always achieved peak performance with my programs at 36 processes sharp. Any higher number of processes resulted in a dramatic slowdown. I took it as a sign that the hyperthreading isn't working well, at least for my application.
But recently a friend ran the same code on a similar workstation with the Dual Intel Xeon Gold 6148 2.4GHz, 3.7GHz, 20C, 10.4GT/s 3UPI, 27M Cache, HT (150W) DDR4-2666. The same program achieved a continuous speedup up to 80 processes!
This makes me wonder if I need to change some option in my system, or install a different compiler version? I'm puzzled. I would appreciate any advise on this issue! Below I'm attaching some details of the two systems (output of cpuinfo and compiler versions).
My system:
===== Processor composition =====
Processor name : Intel(R) Xeon(R) E5-2697 v4
Packages(sockets) : 2
Cores : 36
Processors(CPUs) : 72
Cores per package : 18
Threads per core : 2
ifort (IFORT) 19.0.0.117 20180804
Copyright (C) 1985-2018 Intel Corporation. All rights reserved.
Friend's system:
Processor name : Intel(R) Xeon(R) Gold 6148
Packages(sockets) : 2
Cores : 40
Processors(CPUs) : 80
Cores per package : 20
Threads per core : 2
ifort (IFORT) 19.0.3.199 20190206
Copyright (C) 1985-2018 Intel Corporation. All rights reserved.