Super User is a question and answer site for computer enthusiasts and power users. It's 100% free, no registration required.

Sign up
Here's how it works:
  1. Anybody can ask a question
  2. Anybody can answer
  3. The best answers are voted up and rise to the top

When I use OpenMP in FORTRAN to parallelize a program on linux, ' top' command show me just one processor working ~%800 instead of ~%100 x 8 processors. Is it a expected situation ?

share|improve this question
Turn off Hyperthreading in your bios and see if you still get 800%. I'm guessing you have a 4 core processor with each having 2 threads, ergo "8 processors". – Roman Luštrik Sep 10 '11 at 13:57

What you are seeing is a summation of all threads in the process. You have to tell top to display individual threads. You can do it either by calling top -H or using the H interactive command during top execution.

share|improve this answer

Your Answer


By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.