Closed Bug 659311 Opened 13 years ago Closed 4 years ago

Avoid clobber between profile generate and use passes of PGO builds

Categories

(Firefox Build System :: General, defect)

All
Linux
defect
Not set
normal

Tracking

(Not tracked)

RESOLVED WONTFIX
mozilla9

People

(Reporter: glandium, Assigned: glandium)

References

Details

(Whiteboard: fixed-in-bs)

Attachments

(1 file, 1 obsolete file)

      No description provided.
Attachment #534760 - Flags: review?(ted.mielczarek)
Comment on attachment 534760 [details] [diff] [review]
Avoid clobber between profile generate and use passes of PGO builds

Review of attachment 534760 [details] [diff] [review]:
-----------------------------------------------------------------

This all looks sane, I just have one large reservation here. Any way to test this? (Clearly the try server isn't going to help.)

::: config/rules.mk
@@ +903,5 @@
>  endif # SHARED_LIBRARY || PROGRAM
> +else  # ! WINNT_
> +# Force rebuilding all objects on the second pass
> +$(OBJS): pgo.rebuild
> +.PHONY: pgo.rebuild

Is this going to do weird things to the profiling phase? Presumably you can wind up with object files that aren't compiled with instrumentation because they had no changes, so you wouldn't profile them and then they wouldn't get optimized properly. Is there going to be weird perf impact on a dep build after this?
Attachment #534760 - Flags: review?(ted.mielczarek) → review+
Depends on: 659942
Another possibility would be to try to keep the -fprofile-generate objects around.
(In reply to comment #2)
> Is this going to do weird things to the profiling phase? Presumably you can
> wind up with object files that aren't compiled with instrumentation because
> they had no changes, so you wouldn't profile them and then they wouldn't get
> optimized properly. Is there going to be weird perf impact on a dep build
> after this?

In practice, this is what happens since bug 659942 :(
See bug 676252.
Attachment #534760 - Attachment is obsolete: true
http://hg.mozilla.org/mozilla-central/rev/b0fa6b9a3e47
Status: NEW → RESOLVED
Closed: 13 years ago
Resolution: --- → FIXED
Target Milestone: --- → mozilla9
Depends on: 677191
Product: Core → Firefox Build System

Now that we don't do PGO in one go, it doesn't matter anymore.

Status: REOPENED → RESOLVED
Closed: 13 years ago4 years ago
Resolution: --- → WONTFIX
You need to log in before you can comment on or make changes to this bug.