BUG #8326: pgbench tps wrong BUG

The following bug has been logged on the website:

Bug reference:      8326
Logged by:          digoal.zhou
Email address:      digoal@126.com
PostgreSQL version: Unsupported/Unknown
Operating system:   CentOS 5.8 x64
Description:

when client thread big, the tps without connection time wrong!!!!
pg94@db-172-16-3-33-> pgbench  -M prepared -n -r -f ./test.sql -T 10 -c 800
-j 100 digoal
transaction type: Custom query
scaling factor: 1
query mode: prepared
number of clients: 800
number of threads: 100
duration: 10 s
number of transactions actually processed: 2037960
tps = 199534.267305 (including connections establishing)
tps = 675603.691013 (excluding connections establishing)
statement latencies in milliseconds:
        1.019046        select 1;


when client threads small, the wrong is little.
pg94@db-172-16-3-33-> pgbench  -M prepared -n -r -f ./test.sql -T 10 -c 800
-j 10 digoal
transaction type: Custom query
scaling factor: 1
query mode: prepared
number of clients: 800
number of threads: 10
duration: 10 s
number of transactions actually processed: 1035345
tps = 102285.117970 (including connections establishing)
tps = 115616.181725 (excluding connections establishing)
statement latencies in milliseconds:
        6.812371        select 1;