Bug: Intermittent browser/base/content/test/performance/browser_startup_syncIPC.js | unexpected PWebRenderBridge::Msg_EnsureConnected sync IPC before handling user events -
Status: RESOLVED
Priority: P5
Resolution: DUPLICATE
Created: 2021-06-13 13:41:28+00:00
Resolved: 2022-08-15 12:18:28+00:00

**Filed by:** imoraru [at] mozilla.com
**Parsed log:** https://treeherder.mozilla.org/logviewer?job_id=342626456&repo=try
**Full log:** https://firefox-ci-tc.services.mozilla.com/api/queue/v1/task/c4H8ZcDXRMCUcRpz_jsa8g/runs/0/artifacts/public/logs/live_backing.log

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Observed in today's central-as-early-beta simulation, only happened on macOS DevEdition.

[task 2021-06-13T11:53:15.601Z] 11:53:15     INFO - TEST-START | browser/base/content/test/performance/browser_startup_syncIPC.js
[task 2021-06-13T11:53:15.607Z] 11:53:15     INFO - TEST-INFO | started process screencapture
[task 2021-06-13T11:53:15.728Z] 11:53:15     INFO - TEST-INFO | screencapture: exit 0
[task 2021-06-13T11:53:15.728Z] 11:53:15     INFO - Buffered messages logged at 11:53:15
[task 2021-06-13T11:53:15.729Z] 11:53:15     INFO - Entering test bound 
[task 2021-06-13T11:53:15.729Z] 11:53:15     INFO - known sync IPC before first paint:
[task 2021-06-13T11:53:15.729Z] 11:53:15     INFO -   PWebRenderBridge::Msg_EnsureConnected - at most 1 times
[task 2021-06-13T11:53:15.729Z] 11:53:15     INFO -   PCompositorBridge::Msg_NotifyChildCreated - at most 1 times
[task 2021-06-13T11:53:15.729Z] 11:53:15     INFO -   PCompositorBridge::Msg_FlushRendering - at most 1 times
[task 2021-06-13T11:53:15.730Z] 11:53:15     INFO - TEST-PASS | browser/base/content/test/performance/browser_startup_syncIPC.js | sync IPC PWebRenderBridge::Msg_EnsureConnected happened as many times as expected before first paint - 
[task 2021-06-13T11:53:15.731Z] 11:53:15     INFO - TEST-PASS | browser/base/content/test/performance/browser_startup_syncIPC.js | sync IPC PCompositorBridge::Msg_NotifyChildCreated happened as many times as expected before first paint - 
[task 2021-06-13T11:53:15.731Z] 11:53:15     INFO - TEST-PASS | browser/base/content/test/performance/browser_startup_syncIPC.js | sync IPC PCompositorBridge::Msg_FlushRendering happened as many times as expected before first paint - 
[task 2021-06-13T11:53:15.732Z] 11:53:15     INFO - known sync IPC before handling user events:
[task 2021-06-13T11:53:15.732Z] 11:53:15     INFO -   PCompositorBridge::Msg_FlushRendering - at most 1 times
[task 2021-06-13T11:53:15.732Z] 11:53:15     INFO - Buffered messages finished
[task 2021-06-13T11:53:15.733Z] 11:53:15     INFO - TEST-UNEXPECTED-FAIL | browser/base/content/test/performance/browser_startup_syncIPC.js | unexpected PWebRenderBridge::Msg_EnsureConnected sync IPC before handling user events - 
[task 2021-06-13T11:53:15.733Z] 11:53:15     INFO - Stack trace:
[task 2021-06-13T11:53:15.733Z] 11:53:15     INFO - chrome://mochikit/content/browser-test.js:test_ok:1334
[task 2021-06-13T11:53:15.733Z] 11:53:15     INFO - chrome://mochitests/content/browser/browser/base/content/test/performance/browser_startup_syncIPC.js:null:375
[task 2021-06-13T11:53:15.734Z] 11:53:15     INFO - TEST-PASS | browser/base/content/test/performance/browser_startup_syncIPC.js | sync IPC PCompositorBridge::Msg_FlushRendering allowed 1 more times before handling user events - 
[task 2021-06-13T11:53:15.734Z] 11:53:15     INFO - known sync IPC before becoming idle:
[task 2021-06-13T11:53:15.734Z] 11:53:15     INFO -   PCompositorBridge::Msg_NotifyChildCreated - at most 1 times
[task 2021-06-13T11:53:15.734Z] 11:53:15     INFO -   PCompositorBridge::Msg_FlushRendering - at most 1 times
[task 2021-06-13T11:53:15.735Z] 11:53:15     INFO - TEST-PASS | browser/base/content/test/performance/browser_startup_syncIPC.js | sync IPC PCompositorBridge::Msg_NotifyChildCreated allowed 1 more times before becoming idle - 
[task 2021-06-13T11:53:15.735Z] 11:53:15     INFO - TEST-PASS | browser/base/content/test/performance/browser_startup_syncIPC.js | sync IPC PCompositorBridge::Msg_FlushRendering allowed 1 more times before becoming idle - 
[task 2021-06-13T11:53:15.736Z] 11:53:15     INFO - Not taking screenshot here: see the one that was previously logged
[task 2021-06-13T11:53:15.736Z] 11:53:15     INFO - TEST-UNEXPECTED-FAIL | browser/base/content/test/performance/browser_startup_syncIPC.js | Unexpected sync IPC behavior during startup; open the profile_startup_syncIPC.json artifact in the Firefox Profiler to see what happened - 
[task 2021-06-13T11:53:15.736Z] 11:53:15     INFO - Stack trace:
[task 2021-06-13T11:53:15.736Z] 11:53:15     INFO - chrome://mochikit/content/browser-test.js:test_ok:1334
[task 2021-06-13T11:53:15.737Z] 11:53:15     INFO - chrome://mochitests/content/browser/browser/base/content/test/performance/browser_startup_syncIPC.js:null:412
[task 2021-06-13T11:53:15.737Z] 11:53:15     INFO - Leaving test bound 
[task 2021-06-13T11:53:15.737Z] 11:53:15     INFO - GECKO(1440) | MEMORY STAT | vsize 7203MB | residentFast 305MB | heapAllocated 155MB
[task 2021-06-13T11:53:15.738Z] 11:53:15     INFO - TEST-OK | browser/base/content/test/performance/browser_startup_syncIPC.js | took 41ms
```