apache/spark — pull request #707 by techaddict (2014-05-09 03:18:14+00:00)
Title: SPARK-1775: Unneeded lock in ShuffleMapTask.deserializeInfo

This was used in the past to have a cache of deserialized ShuffleMapTasks, but that's been removed, so there's no need for a lock. It slows down Spark when task descriptions are large, e.g. due to large lineage graphs or local variables.