My general feeling is usually: if something appears not to be necessary, then removing it is usually the easiest way to go, and you probably won't miss it :-D

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/tools/build/+/852c6f0043c86ca5a66549cee5cbb0f54f371e04

commit 852c6f0043c86ca5a66549cee5cbb0f54f371e04
Author: Tim 'mithro' Ansell <tansell@chromium.org>
Date: Thu Feb 16 23:32:34 2017

chromium.fyi: Remove --fully-parallel from RandomOrder bots.

Also adds --seed=4 which should allow us to compare local
run to the run on swarming.

BUG= 692866 , 601332 

Change-Id: Ide57008d2b15c9eb32c18afe351f0f1ff881f838
Reviewed-on: https://chromium-review.googlesource.com/444424
Reviewed-by: Quinten Yearsley <qyearsley@chromium.org>
Reviewed-by: smut <smut@chromium.org>
Reviewed-by: Stephen Martinis <martiniss@chromium.org>
Reviewed-by: John Budorick <jbudorick@chromium.org>
Commit-Queue: Tim 'mithro' Ansell <tansell@chromium.org>

[modify] https://crrev.com/852c6f0043c86ca5a66549cee5cbb0f54f371e04/scripts/slave/recipes/chromium.expected/full_chromium_fyi_WebKit_Win___RandomOrder.json
[modify] https://crrev.com/852c6f0043c86ca5a66549cee5cbb0f54f371e04/scripts/slave/recipes/chromium.expected/full_chromium_fyi_WebKit_Linux___RandomOrder.json
[modify] https://crrev.com/852c6f0043c86ca5a66549cee5cbb0f54f371e04/scripts/slave/recipe_modules/chromium_tests/chromium_fyi.py
[modify] https://crrev.com/852c6f0043c86ca5a66549cee5cbb0f54f371e04/scripts/slave/recipes/chromium.expected/full_chromium_fyi_WebKit_Mac___RandomOrder.json

I think we should just remove the flag.

qyearsley@ / jeffcarp@ - What is the status of this? Is someone going to remove it?

No current plans, but I support removing it. This bug is free for anyone to take :-)

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/e71979baadfbc952e5173e9e1df739f422bdf461

commit e71979baadfbc952e5173e9e1df739f422bdf461
Author: Myung-jong Kim <mjkim610@gmail.com>
Date: Wed Dec 20 18:33:39 2017

Remove --fully-parallel from tests.

Bug:  692866 
Change-Id: I0530db53a88da0eaf8c813f41047832ed6bbbc0d
Reviewed-on: https://chromium-review.googlesource.com/741106
Commit-Queue: Quinten Yearsley <qyearsley@chromium.org>
Reviewed-by: Quinten Yearsley <qyearsley@chromium.org>
Cr-Commit-Position: refs/heads/master@{#525379}
[modify] https://crrev.com/e71979baadfbc952e5173e9e1df739f422bdf461/docs/testing/layout_tests.md
[modify] https://crrev.com/e71979baadfbc952e5173e9e1df739f422bdf461/third_party/WebKit/Tools/Scripts/webkitpy/layout_tests/controllers/layout_test_runner.py
[modify] https://crrev.com/e71979baadfbc952e5173e9e1df739f422bdf461/third_party/WebKit/Tools/Scripts/webkitpy/layout_tests/controllers/layout_test_runner_unittest.py
[modify] https://crrev.com/e71979baadfbc952e5173e9e1df739f422bdf461/third_party/WebKit/Tools/Scripts/webkitpy/layout_tests/run_webkit_tests.py

I'd like to revert this. I'm using -f all the time.

When running fast/multicol/ tests locally now:
Found 628 tests; running 628, skipping 0.
WARNING: fully_parallel flag is deprecated.
Running 9 content_shells in parallel.

Before this CL:
Found 628 tests; running 628, skipping 0.
Running 56 content_shells in parallel.                                                      

(I have 56 logical cores)

Alright -

My original understanding of this bug was:
 (1) --fully-parallel appeared to be equivalent to --run-singly
 (2) --fully-parallel wasn't clearly useful

Since it appears this isn't actually the case, I think we actually want to keep this flag. I've confirmed that on my machine, after this CL 9 content_shells are run in parallel

Although, I seem to recall that rwt used to always set the number of parallel content_shells to match the number of logical cores... maybe I'm remembering incorrectly?

Seems to me that the number of parallel content_shells won't be larger than the number of subdirectories.

Unless you use -f. Then the number of parallel content_shells will be min(the number of tests, the number of logical cores).

Unless we're talking about tests in virtual/. Then we're limited by the number of subdirectories again, even with -f.

Thanks for reverting!

I believe we want to just close this as WontFix after https://crrev.com/c/847872 lands.

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/17bf9b43456ca673be66f5b72bd0e432b6339547

commit 17bf9b43456ca673be66f5b72bd0e432b6339547
Author: Quinten Yearsley <qyearsley@chromium.org>
Date: Wed Jan 03 01:09:59 2018

Revert "Remove --fully-parallel from tests."

This reverts commit e71979baadfbc952e5173e9e1df739f422bdf461.

Reason for revert: mstensho@ reports that this flag is actually still useful and we still want to keep it.

Original change's description:
> Remove --fully-parallel from tests.
> 
> Bug:  692866 
> Change-Id: I0530db53a88da0eaf8c813f41047832ed6bbbc0d
> Reviewed-on: https://chromium-review.googlesource.com/741106
> Commit-Queue: Quinten Yearsley <qyearsley@chromium.org>
> Reviewed-by: Quinten Yearsley <qyearsley@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#525379}

TBR=qyearsley@chromium.org,mjkim610@gmail.com

# Not skipping CQ checks because original CL landed > 1 day ago.

Bug:  692866 
Change-Id: I1d694c1ef7437f784aa2cb2de47850fd68b4d3ab
Reviewed-on: https://chromium-review.googlesource.com/847872
Reviewed-by: Quinten Yearsley <qyearsley@chromium.org>
Reviewed-by: Morten Stenshorne <mstensho@chromium.org>
Commit-Queue: Quinten Yearsley <qyearsley@chromium.org>
Cr-Commit-Position: refs/heads/master@{#526559}
[modify] https://crrev.com/17bf9b43456ca673be66f5b72bd0e432b6339547/docs/testing/layout_tests.md
[modify] https://crrev.com/17bf9b43456ca673be66f5b72bd0e432b6339547/third_party/WebKit/Tools/Scripts/webkitpy/layout_tests/controllers/layout_test_runner.py
[modify] https://crrev.com/17bf9b43456ca673be66f5b72bd0e432b6339547/third_party/WebKit/Tools/Scripts/webkitpy/layout_tests/controllers/layout_test_runner_unittest.py
[modify] https://crrev.com/17bf9b43456ca673be66f5b72bd0e432b6339547/third_party/WebKit/Tools/Scripts/webkitpy/layout_tests/run_webkit_tests.py

This issue has been Available for over a year. If it's no longer important or seems unlikely to be fixed, please consider closing it out. If it is important, please re-triage the issue.

Sorry for the inconvenience if the bug really should have been left as Available.

For more details visit https://www.chromium.org/issue-tracking/autotriage - Your friendly Sheriffbot

WontFix as per comment 12.