All graphs for this bug:
  https://chromeperf.appspot.com/group_report?bug_id=886668

(For debugging:) Original alerts at time of bug-filing:
  https://chromeperf.appspot.com/group_report?sid=311ff5c59a18783b86d4e7ea93b571edec75eefab04ee4d6c5b6077c2d28dc2e


Bot(s) for this bug's original alert(s):

Android Nexus5 Perf
android-nexus5x-perf

system_health.common_mobile - Benchmark documentation link:
  https://bit.ly/system-health-benchmarks

📍 Pinpoint job started.
https://pinpoint-dot-chromeperf.appspot.com/job/12274c0f640000

📍 Found a significant difference after 1 commit.
https://pinpoint-dot-chromeperf.appspot.com/job/12274c0f640000

[config] Enable scheduled script streaming field trial by leszeks@chromium.org
https://chromium.googlesource.com/chromium/src/+/7eb2bb6769b38736fc75a12c15563c4a69f1a61f
849.7 → 1126 (+276.7)

Understanding performance regressions:
  http://g.co/ChromePerformanceRegressions

Benchmark documentation link:
  https://bit.ly/system-health-benchmarks

+Alexander, these are the traces we discussed earlier where streaming compilation appears to be blocking the image controller from performing StopWorkerTasks

 Issue 886669  has been merged into this issue.

Etienne+Gab, I believe this would be solved by the MayBlock/NonBlock pool merge.

@etiennep : when you land your experiment code (https://chromium-review.googlesource.com/c/chromium/src/+/1249836), let's also make it the default in fieldtrial_testing_config.json so we get data from the perf bots (and, among other things, see if it addresses this).

FYI, I was planning to disable this field trial until the pools are merged (https://chromium-review.googlesource.com/1255946). I'd rather re-enable in a separate CL to get separate data.

Ok SG, I think we should land the merge experiment enabled-for-testing anyways so we see what else it potentially impacts (independent of script streaming).

Agreed, I'll watch for this landing and will re-enable scheduled streaming a day or two later.

SG, I'll land experiment code with enabled-for-testing soon.

I may be wrong, but my understanding is that enable-for-testing enables the feature on correctness testing bots (e.g. LayoutTests) but not perf bots. To enable it there I think you need a field trial, i.e. something like: https://chromium-review.googlesource.com/c/chromium/src/+/1226604

Thanks for doing this!

That's precisely what I meant by make the experiment enabled-for-testing (does it have another signification?)

Ahh, I was thinking you meant this:
https://cs.chromium.org/chromium/src/third_party/blink/renderer/platform/runtime_enabled_features.json5?q=Runtime_enable&sq=package:chromium&g=0&l=13

Or something similar out-with Blink. SG, thanks.

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/1ed3b3c26c8366db8fc93bbd57b30f97fa79a7e5

commit 1ed3b3c26c8366db8fc93bbd57b30f97fa79a7e5
Author: Leszek Swirski <leszeks@chromium.org>
Date: Wed Oct 03 10:44:00 2018

[config] Disable scheduled script streaming field trial

Measure the impact of the current trial by seeing what regressed, and
disable while waiting for Bug:874080 to be resolved, since there are
currently some loading regressions.

Bug:  715309 
Bug: 885053
Bug:  886668 
Change-Id: I4497e11373ffa92d3e5f5844fa9fbe73fef6bf4b
Reviewed-on: https://chromium-review.googlesource.com/c/1255946
Reviewed-by: Ross McIlroy <rmcilroy@chromium.org>
Reviewed-by: Steven Holte <holte@chromium.org>
Commit-Queue: Leszek Swirski <leszeks@chromium.org>
Cr-Commit-Position: refs/heads/master@{#596175}
[modify] https://crrev.com/1ed3b3c26c8366db8fc93bbd57b30f97fa79a7e5/testing/variations/fieldtrial_testing_config.json

 Issue 886667  has been merged into this issue.

 Issue 886666  has been merged into this issue.

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/83ec360fbb41f7b81a628417b1aa5f13daaa622d

commit 83ec360fbb41f7b81a628417b1aa5f13daaa622d
Author: Leszek Swirski <leszeks@chromium.org>
Date: Wed Nov 21 16:50:55 2018

Revert "[config] Disable scheduled script streaming field trial"

This reverts commit 1ed3b3c26c8366db8fc93bbd57b30f97fa79a7e5.

Reason for revert: Re-enabling the trial now that 874080 is being
field tested.

Original change's description:
> [config] Disable scheduled script streaming field trial
> 
> Measure the impact of the current trial by seeing what regressed, and
> disable while waiting for Bug:874080 to be resolved, since there are
> currently some loading regressions.
> 
> Bug:  715309 
> Bug: 885053
> Bug:  886668 
> Change-Id: I4497e11373ffa92d3e5f5844fa9fbe73fef6bf4b
> Reviewed-on: https://chromium-review.googlesource.com/c/1255946
> Reviewed-by: Ross McIlroy <rmcilroy@chromium.org>
> Reviewed-by: Steven Holte <holte@chromium.org>
> Commit-Queue: Leszek Swirski <leszeks@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#596175}

TBR=rmcilroy@chromium.org,holte@chromium.org,leszeks@chromium.org

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

Bug:  715309 , 885053,  886668 
Change-Id: I59f9e0d1f5b97a75d7d81e98471cd21a3a68888b
Reviewed-on: https://chromium-review.googlesource.com/c/1296502
Reviewed-by: Steven Holte <holte@chromium.org>
Commit-Queue: Leszek Swirski <leszeks@chromium.org>
Cr-Commit-Position: refs/heads/master@{#610107}
[modify] https://crrev.com/83ec360fbb41f7b81a628417b1aa5f13daaa622d/testing/variations/fieldtrial_testing_config.json

Re-enabling the trial did not reproduce the error, considering this fixed.