I wanted to share some performance numbers to encourage others to write examples or applications using the C++ multi-core mapreduce library being developed by Craig H. I ran some tests comparing the C++ version to the C version, for the word_count example. The tests are run on a X86_64 linux Fedora 10 with 2 cores. The results below show that the C++ MapReduce (mr) has very similar performance to the C version (mr-c). The tests start running phoenix first. Run 3 and 4 show that c++ mr is slightly faster. When using 1MB MR_L1CACHESIZE (which should be the best comparison) shows that mr-c is a little bit faster but not much. 1-mr-c 0m18.077s 2-mr 0m13.818s 3-mr-c 0m14.828s 4-mr 0m14.148s 5-mr-c-1MB 0m14.006s 6-mr-c-2MB 0m14.084s Note: The C++ version uses a chunk size of 1MB while the C version uses by default a chunk size of 64KB (which can be changed with the variable MR_L1CACHESIZE) regards jose