"plugin-normal": simply mysql-5.1.29 and innodb_plugin-1.0.1
"plugin-rw": "plugin-normal added innodb_rw_lock.patch

File format - old InnoDB format (not Barracuda)

Install:
  It was compiled with mysql-5.1.29 as the description of the page.
  http://www.innodb.com/doc/innodb_plugin-1.0/innodb-plugin-installation.html#innodb-plugin-installation-source-unix

benchmark:

Xeon E5310 (Quad 1.6GHz) x 2
TPC-C (removed UPDATE of w_ytd and d_ytd for scale at small WH)
Warehouse (WH:scale factor): 1WH
Storage: ramfs (for CPU bound)

results

      5.0-normal 5.0-rw-split 5.1-normal 5.1-rw-split plugin-normal plugin-rw
2core   13837.67     13815      13292.33     13393.67      12907.33  12983.67
4core   24064.33     24138.67   23309.67     23555         22433.33  22590.33
8core   35663.33     36431.33   34991        35699.67      33012     33123.33