I need to test performance of a multithreaded program on 1 CPU, but I have a dual CPU machine. I need to set affinity to those logical CPU's, that share their socket, oterwise they strongly benefit from larger number of FSB's. I tried affinity 0-7 and 8-15, but the results differ considerably, the first being faster. Therefore I do not know which logical CPU's share their socket.
lscpu Architecture: x86_64 CPU op-mode(s): 32-bit, 64-bit Byte Order: Little Endian CPU(s): 16 On-line CPU(s) list: 0-15 Thread(s) per core: 1 Core(s) per socket: 8 CPU socket(s): 2 NUMA node(s): 4 Vendor ID: AuthenticAMD CPU family: 16 Model: 9 Stepping: 1 CPU MHz: 800.000 BogoMIPS: 4000.40 Virtualization: AMD-V L1d cache: 64K L1i cache: 64K L2 cache: 512K L3 cache: 5118K NUMA node0 CPU(s): 0-3 NUMA node1 CPU(s): 4-7 NUMA node2 CPU(s): 12-15 NUMA node3 CPU(s): 8-11 ~]$ cat /proc/cpuinfo | grep 'core id' core id : 0 core id : 1 core id : 2 core id : 3 core id : 0 core id : 1 core id : 2 core id : 3 core id : 0 core id : 1 core id : 2 core id : 3 core id : 0 core id : 1 core id : 2 core id : 3