HADOOP-6949 introduced a very important optimization to the RPC layer. Based
on the benchmarks presented in HDFS-1583 this provides an order of magnitude
improvement of current RPC implementation.
RPC is a common component of Hadoop projects. Many of them should benefit
from this change. But since this is an incompatible change it requires a
vote to be included into a previous branch.
Please vote for inclusion of this change into branch 0.22.
+1 from me.