Using gettimeofday for testing the effects of NO_HZ_FULL on context switch duration may not be measuring anything that changes with regards to NO_HZ_FULL. gettimeofday is implemented via VDSO, and is not an actual system call that requires a context switch.
Gerald,
Using gettimeofday for testing the effects of NO_HZ_FULL on context switch duration may not be measuring anything that changes with regards to NO_HZ_FULL. gettimeofday is implemented via VDSO, and is not an actual system call that requires a context switch.