Added max # of threads to a benchmark.
Added max # of threads to a benchmark.

hemingcui/xtern_with_paxos,hemingcui/xtern_with_paxos,columbia/xtern,hemingcui/xtern_with_paxos,columbia/xtern,columbia/xtern,hemingcui/xtern_with_paxos,columbia/xtern,columbia/xtern,columbia/xtern,hemingcui/xtern_with_paxos