Multi-core single-threaded processor, not reaching 100%

Question

As you can see from the attached image, the CPU graph on my dual-core machine is strangely symmetrical!

Is it some kind of load balancing to prevent the use of one core more than another? What are the reasons for this (heat distribution may be)?

Of course, my main problem is: does my PSNR single-stream image algorithm reach 100%?

The Core 2 Duo E6850 3Ghz processor is running Ubuntu 10.4.

thanks

Ross

Answer 1

You reach 50% of the load using both processors. Your program is not tied to a fixed processor, so it switches depending on the kernel (and other processes running on your system).

If you want to make sure that your process is running on one of your cores, you need to set an affinity ( Example here ). Thus, you should see 100% load on one core, and the other on other tasks.

Answer 2

(Should have used comments for this, but I don't have enough reputation!)

I came across this situation more than once and always with application conflict.

For example, this can happen when the compiler is started twice, or when it is partially unset. I found that this could also happen when reading DVDs with two different players at the same time.

In my experience, this is not normal behavior: the computer slows down quite a bit, which is annoying when you try to fix it!