How to Profile Golang application using pprof

Once you have the Golang application running and exposing the profiler endpoint we can take a snapshot:

PROFILING_PORT=3888
curl -sS -o "/tmp/app_heap_t0.pb.gz" "http://127.0.0.1:${PROFILING_PORT}/debug/pprof/heap?gc=1"

Then we do the actions that cause a memory spike and we take another snapshot:

curl -sS -o "/tmp/app_heap_t1.pb.gz" "http://127.0.0.1:${PROFILING_PORT}/debug/pprof/heap?gc=1"

And we compare them:

go tool pprof --base /tmp/app_heap_t0.pb.gz /tmp/app_heap_t1.pb.gz

Useful commands inside the comparison:

(pprof) top
(pprof) top -cum

We can use to show Go objects instead of sizes:

(pprof) sample_index=inuse_objects  

If we'd like to also get a snapshot of the goroutines and memory allocations, we can use:

curl -sS -o "/tmp/pprof_app_goroutines" "http://127.0.0.1:${PROFILING_PORT}/debug/pprof/goroutine?debug=2"
curl -sS -o "/tmp/pprof_app_allocs" "http://127.0.0.1:${PROFILING_PORT}/debug/pprof/allocs?seconds=30"