Electrolysis/Release Criteria/Slow Script: Difference between revisions

Electrolysis/Release Criteria/Slow Script (view source)

Revision as of 21:17, 22 February 2016

2,450 bytes added , 22 February 2016

Add more info about current state.

Azhang

10

edits

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 Analysis was reviewed by: rvitillo
-Open questions: have we tested the metric to make sure it's working properly in e10s?
+How slow script notice count works on non-e10s:
+* '''nsGlobalWindow::ShowSlowScriptDialog''' accumulates the SLOW_SCRIPT_NOTICE_COUNT histogram (https://dxr.mozilla.org/mozilla-central/source/dom/base/nsGlobalWindow.cpp#10677)
+How slow script notice count works on e10s:
+* [CHILD] '''nsGlobalWindow::ShowSlowScriptDialog''' sends a slow script notification via '''ProcessHangMonitor::NotifySlowScript''' (https://dxr.mozilla.org/mozilla-central/source/dom/base/nsGlobalWindow.cpp#10652)
+* [CHILD] '''HangMonitorChild::NotifySlowScript''' invokes '''HangMonitorChild::NotifySlowScriptAsync''' to send out the slow script notice (https://dxr.mozilla.org/mozilla-central/source/dom/ipc/ProcessHangMonitor.cpp#352)
+* [CHILD] '''PProcessHangMonitorChild::SendHangEvidence''' invokes '''PProcessHangMonitorParent::OnMessageReceived''' via IPC (https://dxr.mozilla.org/mozilla-central/source/obj-x86_64-unknown-linux-gnu/ipc/ipdl/PProcessHangMonitorChild.cpp#108)
+* [PARENT] '''HangMonitorParent::RecvHangEvidence''' is called when '''PProcessHangMonitorParent''' receives a message from the child process (https://dxr.mozilla.org/mozilla-central/source/obj-x86_64-unknown-linux-gnu/ipc/ipdl/PProcessHangMonitorParent.cpp#288)
+* [PARENT] '''HangMonitorParent::RecvHangEvidence''' sends out a "process-hang-report" event by creating a '''HangObserverNotifier''' task (https://dxr.mozilla.org/mozilla-central/source/dom/ipc/ProcessHangMonitor.cpp#610)
+* [PARENT] '''ProcessHangMonitor.reportHang''' is called when the '''ProcessHangMonitor''' receives a "process-hang-report" event (https://dxr.mozilla.org/mozilla-central/source/browser/modules/ProcessHangMonitor.jsm#66)
+* [PARENT] JS function '''ProcessHangMonitor.reportHang''' accumulates the SLOW_SCRIPT_NOTICE_COUNT histogram (https://dxr.mozilla.org/mozilla-central/source/browser/modules/ProcessHangMonitor.jsm#403)
+* I've checked that this is currently the only code path that results in SLOW_SCRIPT_NOTICE_COUNT being incremented.
+Have we tested the metric to make sure it's working properly in e10s?
+* There should be no differences in the slow script '''reporting''' mechanism between e10s and non-e10s; 1 call to ShowSlowScriptDialog means 1 addition to the histogram regardless of e10s setting. Manual testing supports this.
+* The timeout has changed from 2 to 10 in e10s builds (see https://hg.mozilla.org/mozilla-central/rev/63680efe6d55#l35.12 for before and https://hg.mozilla.org/mozilla-central/rev/5002e9c06365#l2.13 for after). :azhang is currently investigating this.