Significant performance regression using TokuDB tables in mariadb.org builds

In testing the performance of TokuDB tables using the MariaDB builds (available from mariadb.org) I noticed significant performance regressions. The following is for Sysbench (data > cache, IO bound):
workload = read/write
tables = 16
distribution = uniform
rows / table = 10 million
tokudb_cache_size = 8G
tokudb_directio = 1
tokudb_read_block_size = 64K
tokudb_row_format = tokudb_lzma
performance_schema=off

Table are bulk-loaded, then ran the test for 64 and 128 client threads, 5 minutes per thread count. Results as follows:

MariaDB 10.0.8 : source = mariadb.org
64 threads, 78.0 tps
128 threads, 95.6 tps

MariaDB 5.5.36 : source = mariadb.org
64 threads, 78.4 tps
128 threads, 95.8 tps

MariaDB 5.5.30 : source = tokutek.com
64 threads, 132.3 tps
128 threads, 161.5 tps

MySQL 5.5.30 : source = tokutek.com
64 threads, 134.8 tps
128 threads, 164.1 tps

MySQL 5.5.36 : source = tokutek.com
64 threads, 131.2 tps
128 threads, 161.4 tps