How long does a context switch take in Linux?

Question

I'm curious how many cycles it takes to change contexts in Linux. I'm specifically using an E5405 Xeon (x64), but I'd love to see how it compares to other platforms as well.

Answer 1

There`s a free app called LMBench written by Larry McVoy and friends. It provides a bunch of OS & HW benchmarks One of the tests is called lat_ctx and it measures contex switch latencies. Google for lmbench and check for yourself on your own HW. Its the only way to get a number meaningful to you.

Gilad