Sandy Ryza created MAPREDUCE-5578:
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Summary: Miscellaneous Fair Scheduler speedups
Key: MAPREDUCE-5578
URL: https://issues.apache.org/jira/browse/MAPREDUCE-5578
Project: Hadoop Map/Reduce
Issue Type: Improvement
Components: scheduler
Reporter: Sandy Ryza
Assignee: Sandy Ryza
I ran the Fair Scheduler's core scheduling loop through a profiler to and
identified a bunch of minimally invasive changes that can shave off a few
milliseconds.
The main one is demoting a couple INFO log messages to DEBUG, which brought my
benchmark down from 16000 ms to 6000.
A few others (which had way less of an impact) were
* Most of the time in comparisons was being spent in Math.signum. I switched
this to direct ifs and elses and it halved the percent of time spent in
comparisons.
* I removed some unnecessary instantiations of Resource objects
* I made it so that queues' usage wasn't calculated from the applications up
each time getResourceUsage was called.
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