usleep(3) and nanosleep(2) have better granularity with CFS scheduler in RHEL6

Solution Verified - Updated -

Issue

  • According to top, tcsh is taking up 10%+ CPU in loop with 1 ms sleep.
$ echo 'while 1; usleep 1000; end;' | tcsh -fs

Environment

  • Red Hat Enterprise Linux (RHEL) 6

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