Poor performance in my pgpool cluster

I've configured a postgres cluster with pgpool2 using the following link . The replication seems to be ok, but I ran some benchmarks (pg_bench) and the performance is lower than a single node, for example: > pgbench -c 16 -j 16 -T 600 -S bench2 -h "ONE SINGLE POSTGRES NODE" -p > 5432 number of transactions actually processed: 7752147 tps = > 12920.095988 (including connections establishing) tps = 12921.661448 (excluding connections establishing) > > pgbench -c 16 -j 16 -T 600 -S bench2 -h "PGPOOLNODE" -p 5432 number of > transactions actually processed: 389800 tps = 648.857810 (including > connections establishing) tps = 648.886713 (excluding connections > establishing) > > pgbench -c 16 -j 16 -T 600 -S bench2 -h "MASTERNODE"-p 5432 number of > transactions actually processed: 7093473 tps = 11822.379159 (including > connections establishing) tps = 11823.337051 (excluding connections > establishing) Each node is configured default. All nodes are identical virtaul machines and over the same network. This is my pgpool.conf: listen_addresses = '*' port = 5432 socket_dir = '/var/run/postgresql' pcp_port = 9898 pcp_socket_dir = '/var/run/postgresql' backend_hostname0 = '192.168.1.177' backend_port0 = 5432 backend_weight0 = 0 backend_data_directory0 = '/var/lib/postgresql/9.1/main' backend_flag0 = 'ALLOW_TO_FAILOVER' backend_hostname1 = '192.168.1.175' backend_port1 = 5432 backend_weight1 = 1 backend_data_directory1 = '/var/lib/postgresql/9.1/main' backend_flag1 = 'ALLOW_TO_FAILOVER' backend_hostname2 = '192.168.1.176' backend_port2 = 5432 backend_weight2 = 1 backend_data_directory2 = '/var/lib/postgresql/9.1/main' backend_flag2 = 'ALLOW_TO_FAILOVER' enable_pool_hba = off authentication_timeout = 60 ssl = off num_init_children = 32 max_pool = 4 child_life_time = 300 child_max_connections = 0 connection_life_time = 0 client_idle_limit = 0 log_destination = 'stderr' print_timestamp = on log_connections = on log_hostname = off log_statement = on log_per_node_statement = on log_standby_delay = 'none' syslog_facility = 'LOCAL0' syslog_ident = 'pgpool' debug_level = 0 pid_file_name = '/var/run/postgresql/pgpool.pid' logdir = '/var/log/postgresql' connection_cache = on reset_query_list = 'ABORT; DISCARD ALL' replication_mode = off replicate_select = off insert_lock = on lobj_lock_table = '' replication_stop_on_mismatch = off failover_if_affected_tuples_mismatch = off load_balance_mode = on ignore_leading_white_space = on white_function_list = '' black_function_list = 'nextval,setval' master_slave_mode = on master_slave_sub_mode = 'stream' sr_check_period = 0 sr_check_user = 'ZZZ' sr_check_password = 'YYY' delay_threshold = 0 follow_master_command = '' parallel_mode = off enable_query_cache = off pgpool2_hostname = '' system_db_hostname = 'localhost' system_db_port = 5432 system_db_dbname = 'pgpool' system_db_schema = 'pgpool_catalog' system_db_user = 'pgpool' system_db_password = 'zzz' health_check_period = 0 health_check_timeout = 20 health_check_user = 'pgpool' health_check_password = 'zzz' failover_command = '/var/lib/postgresql/bin/failover.sh %d %M %m' failback_command = '' fail_over_on_backend_error = on recovery_user = 'nobody' recovery_password = '' recovery_1st_stage_command = '' recovery_2nd_stage_command = '' recovery_timeout = 90 client_idle_limit_in_recovery = 0 relcache_expire = 0 Any suggestion? Thanks