A quick and rough example of how Protobuf performance is affected by message size.
python simple.py
simple_string serialization
averaged 5.30099868774 usec
simple_int serialization
averaged 4.469871521 usec
simple_big_int serialization
averaged 4.7459602356 usec
simple_enum serialization
averaged 7.65991210938 usec
python two.py
two_string serialization
averaged 7.64107704163 usec
two_int serialization
averaged 6.16502761841 usec
two_big_int serialization
averaged 9.50288772583 usec
two_enum serialization
averaged 5.70797920227 usec
python complex.py
one thing
averaged 17.2991752625 usec
two things
averaged 65.2959346771 usec
three things
averaged 87.9311561584 usec
four things
averaged 106.728076935 usec
five things
averaged 121.932983398 usec
six things
averaged 146.115064621 usec
1 lot of things
averaged 17.5409317017 usec
3 lots of things
averaged 2329.63895798 usec
4 lots of things
averaged 27911.8249416 usec