dom/browser-element/mochitest/priority/CAUTION@6474c204b198 (annotated)
dom/browser-element/mochitest/priority/CAUTION
Wed, 31 Dec 2014 06:09:35 +0100
- author
- Michael Schloh von Bennewitz <michael@schloh.com>
- date
- Wed, 31 Dec 2014 06:09:35 +0100
- changeset 0
- 6474c204b198
- permissions
- -rw-r--r--
Cloned upstream origin tor-browser at tor-browser-31.3.0esr-4.5-1-build1
revision ID fc1c9ff7c1b2defdbc039f12214767608f46423f for hacking purpose.
| michael@0 | 1 | A word to the wise: |
| michael@0 | 2 | |
| michael@0 | 3 | You must ensure that if your test finishes successfully, no processes have |
| michael@0 | 4 | priority FOREGROUND_HIGH. |
| michael@0 | 5 | |
| michael@0 | 6 | If you don't do this, expect to see tests randomly fail with mysterious |
| michael@0 | 7 | FOREGROUND --> FOREGROUND priority transitions. |
| michael@0 | 8 | |
| michael@0 | 9 | What's happening in this case is that your FOREGROUND_HIGH process lives until |
| michael@0 | 10 | the beginning of the next test. This causes the process started by the next |
| michael@0 | 11 | test to have low CPU priority. Then the FOREGROUND_HIGH process dies, because |
| michael@0 | 12 | its iframe gets GC'ed, and we transition the new test's process from low CPU |
| michael@0 | 13 | priority to regular CPU priority. |
| michael@0 | 14 | |
| michael@0 | 15 | Ouch. |
