1680584 - profileserver.py failures aren't shown when doing full PGO build

Status: RESOLVED INVALID

(Firefox Build System :: General, defect, P3)

Description

[Mitchell Hentges [:mhentges] 🦀]

When doing MOZ_PGO=1, as documented here Firefox does :

1. [subprocess, pipe output] Perform a Firefox build that will generate performance stats
2. [subprocess, check_call] Run a bunch of tests with the built Firefox to get performance stats
3. [subprocess, pipe output] Perform a Firefox build using the generated performance stats

Unfortunately, if step 2 (profilerserver.py) fails, then the output isn't shown, so it's hard to debug.
We should pipe the output of profileserver.py so debugging profiling failures is easier.

Comment 1

[Connor Sheehan [:sheehan]]

Attachment: Bug 1680584: capture and display output of `profileserver.py` r?#build,mhentges

Switches the invocation of profileserver.py from using subprocess.check_call
to subprocess.run. Checks the return code of the profileserver process and
returns it if it is non-zero. profileserver.py only prints output to the
screen when it encounters an error, so this change shouldn't cause any new
output during the build unless an error is encountered.

Comment 2

[Connor Sheehan [:sheehan]]

After taking a closer look it seems the errors are indeed displayed when doing a full PGO build.