Profiling

This is a great opportunity to start using "perf" from the Linux kernel. Some existing perfkit code could be used. Mostly likely the graph rendering and animation code.

• add tracepoint
• enable/disable tracepoint
• view runtime statistics (avg, total, cumulative) and sort by stats
• sample based profiling
• perf timechart?
• network and io throughput
• gtk main loop profiling for stalls
• GPU io bandwidth