mysql-proxy only using one cpu core?

[Justin Albstmeijer]

I have been doing some loadtest on a quadcore server, and found mysql-proxy (0.6.1 on rh4) only using one cpu core when using 70+ mysql client instances in parallel with 3 mysql backends.
Can this be right? is this by design?

top output on mysql-proxy host.

Cpu0 : 0.3% us, 0.0% sy, 0.0% ni, 85.8% id, 0.0% wa, 0.3% hi, 13.6% si
Cpu1 : 0.3% us, 0.0% sy, 0.0% ni, 99.7% id, 0.0% wa, 0.0% hi, 0.0% si
Cpu2 : 79.7% us, 14.0% sy, 0.0% ni, 0.0% id, 0.0% wa, 0.0% hi, 6.3% si
Cpu3 : 0.0% us, 0.0% sy, 0.0% ni, 100.0% id, 0.0% wa, 0.0% hi, 0.0% si