Messages in this thread | | | Date | Sat, 11 Sep 2010 13:37:32 -0400 | From | Mathieu Desnoyers <> | Subject | [RFC patch 0/2] sched: dynamically adapt granularity with nr_running |
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Changing the minimum granularity is a double-edged sword: if we set it to a too small value, then the scheduler will preempt tasks too often. If it is too large, then the "latency" period can grow very large as the number of running tasks increases.
The first patch leaves the same scheduling granularity when there are few tasks on the system (3 or less), but dynamically adapts (shrinks) the sched granularity when there are more. At a ceiling value of 8 running tasks (this choice is arbitrary), it grows the latency rather than shrinking granularity further to ensure we don't end up calling the scheduler too often.
The second patch ensures that awakened sleeping tasks don't get affected by shrinked minimum granularity.
Comments are welcome,
Thanks,
Mathieu
-- Mathieu Desnoyers Operating System Efficiency R&D Consultant EfficiOS Inc. http://www.efficios.com
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