message: fuzz: coverage profile generation instructions.
diff: @@ -122,3 +122,23 @@ source directory for the test, e.g. for `server_fuzz_test` this is
  //test/server:server_fuzz_test`. These crash cases can be added to the corpus in
  followup PRs to provide fuzzers some interesting starting points for invalid
  inputs.
  +
  +## Coverage reports
  +
  +Coverage reports, where individual lines are annotated with fuzzing hit counts,
  +are a useful way to understand the scope and efficacy of the Envoy fuzzers. You
  +can generate such reports from the ClusterFuzz corpus following the general
  +ClusterFuzz [instructions for profiling
  +setup](https://github.com/google/oss-fuzz/blob/master/docs/code_coverage.md).
  +
  +To filter out unrelated artifacts (e.g. Bazel cache, libfuzzer src), the
  +following profile command can be used:
  +
  +```bash
  +python infra/helper.py profile envoy -- \
  + -ignore-filename-regex='proc/self/cwd/bazel-out.*' \
  + -ignore-filename-regex='proc/self/cwd/external.*' \
  + -ignore-filename-regex='proc/self/cwd/test.*' \
  + -ignore-filename-regex='.*\.cache.*' \
  + -ignore-filename-regex='src/libfuzzer.*'
  +```
  