713778 - nsICycleCollectorListener should not enable trace_all by default

Status: RESOLVED FIXED

(Core :: XPCOM, defect)

Description

[Olli Pettay [:smaug][[e-mail]]]

We optimize many edges out, but nsICycleCollectorListener doesn't know about it

Comment 1

[Olli Pettay [:smaug][[e-mail]]]

Attachment: patch

This changes the default to be more useful, IMO, but the old
WANT_ALL_TRACES is still possible if one
uses
window.QueryInterface(Components.interfaces.nsIInterfaceRequestor).
  getInterface(Components.interfaces.nsIDOMWindowUtils).
  garbageCollect(Components.classes["@mozilla.org/cycle-collector-logger;1"]
    .createInstance(Components.interfaces.nsICycleCollectorListener).allTraces())

So, it is enough to just call allTraces(), and since the method returns the listener itself, 
no need to store the listener in any temporary variable.

Comment 2

[Andrew McCreight [:mccr8]]

Comment on attachment 585081 [details] [diff] [review]
patch

Review of attachment 585081 [details] [diff] [review]:
-----------------------------------------------------------------

Nice.  I think this will be a more useful default.  WANT_ALL_TRACES is good for leak hunting, but not for CC performance analysis.

I assume the existing JS incantation will continue to work?  If not, you should update the wiki entry at https://wiki.mozilla.org/Performance:Leak_Tools#Cycle_collector_heap_dump .  Either way, you should probably add this new way to invoke it there.

Comment 3

[Olli Pettay [:smaug][[e-mail]]]

https://hg.mozilla.org/mozilla-central/rev/d98fbf3cbd71

I updated also the wiki page.