apache/incubator-spark — pull request #43 by mateiz (2013-10-08 02:20:00+00:00)
Title: Don't allocate Kryo buffers unless needed

I noticed that the Kryo serializer could be slower than the Java one by 2-3x on small shuffles because it spend a lot of time initializing Kryo Input and Output objects. This is because our default buffer size for them is very large. Since the serializer is often used on streams, I made the initialization lazy for that, and used a smaller buffer (auto-managed by Kryo) for input.