[SOLVED] Viewing source code in pprof with bazel built binary

Viewing source code in pprof with bazel built binary

I am trying to profile a binary that I've built under bazel using pprof. I am able to generate a profile, however when I view it in the web UI, I cannot see my code in the source code view. I see ??s instead.

Here are the commands I'm using:

CPUPROFILE=/tmp/cpu_profile bazel run --linkopt='-lprofiler' //my:binary

pprof -http=localhost:8000 -lines bazel-bin/my/binary /tmp/cpu_profile

How can I access the source code information?

Solution

By default, bazel builds binaries using the fastbuild compilation_mode which doesn't have all of the necessary debug information needed to link the source.

To fix this, profile using dbg mode:

CPUPROFILE=/tmp/cpu_profile bazel run -c dbg \
  --linkopt='-lprofiler' \
  //my:binary

Or include debug information in an optimized build:

CPUPROFILE=/tmp/cpu_profile bazel run -c opt \
  --copt=-g \
  --linkopt='-lprofiler' \
  //my:binary