Hi,

I am using Intel Parallel Studio XE 2015 on two different workstations. One has single Intel Xeon X5570 ( 8 cores ) processor with RHEL 5 Operating System lets called it workstation1 and Second has two Intel Xeon E5-2690 v3 (12 core each CPU) with RHEL 7 Operating System called it workstation2. I run same C++ code in both workstations with different number of thread but in Workstation1 with increase in number of thread up to 8 I get reduction in time exponentially but with same is not go well with workstation2. In workstation2 with increasing number of threads upto 12 I get reduction in time but not as good as I get in workstation1 and after 12 threads it there is increment of time as well with increment of threads. I am not able to understand why workstation2 with higher computing capacity is not able to perform better than workstation1 and why there is performance lagging in workstation2 with increasing number of thread. Kindly provide solution to my problem.



Thanks in advance

rdg006

I am presuming process loads are identically sized. Your question is otherwise meaningless. Two differences are immediately obvious:

1. 12 processes vs 8 puts more load on the data bus. How they behaved at 8 processes each would be informative.

2. RHEL 5 will be a smaller overhead with libc5 whereas RHEL 7 is a good few generations into libc6, later kernel, etc. You would expect a greater system overhead.

You never compared the background process loads, bus & disk speeds, tmp storage or even the cpus properly. You need to investigate.