Go Benchmarking

Table of Contents

• cpuprofile
• memprofile
• pprof
  • views

The benchmark cycle:

1. write a benchmark
2. run a benchmark
3. get a profile
4. optimise
5. run your tests
6. goto 2.

cpuprofile

go test -test=XXX -bench <regex> -cpuprofile <file>

memprofile

go test -test=XXX -bench <regex> -memprofile <file> -benchmem

pprof

pprof usage

go pprof -http=:8080 profile.pb.gz

will show a web UI for analysing the profile.

views

• flame graph: localhost:8080/ui/flamegraph
  • shows percentage breakdown of how much resource each "call" made.
  • clicking a box will make it "100%" allowing for deep diving
  • right click "show source code" to view
• top: localhost:8080/ui/top
  • shows top functions
    • flat: profile samples in this function
    • cum: (cumulative) profile samples in this function and its callees
• source: localhost:8080/ui/source
  • each source line is annotated with the time spent in that source line
    • the first number does not count time spent in functions called from the source line
    • the second number does