How to Profile Google App Engine Java Servlet

I have a java google app engine servlet that writes to the datastore amongst other things. It runs reall开发者_运维问答y fast locally. However, on app engine server each request nears 2 seconds (event after ramp up). How can I go about profiling my servlet to identify which pieces of my code are taking long?

So far the only way I can think of is to log system time at various points in the code and then look at the logs and work it out... is there a better technique to do it?

Use appstats, a tool written specifically for profiling RPC calls on App Engine.