On Oct 29, 2010, at 4:01 PM, felix wrote: > On 10/29/10 15:18, Jim Deville wrote: >> C# 4.0 has WeakMap's too, and one of the goals was to work around the >> cyclical reference issue: >> >> http://blogs.msdn.com/b/clrteam/archive/2009/05/18/the-conditional-weak-table-enabling-dynamic-object-properties.aspx > > mono implements ConditionalWeakTable with Ephemeron tables registered with > the GC. The registration does nothing with boehm-gc, but there is special > handling for Ephemerons in the experimental sgen-gc, and it looks to me like > it's similar to what's described on the ECMAScript wiki for WeakMap: > repeatedly scan Ephemeron key,value entries for values that are newly > reachable, until no more newly-reachable values are found. > > http://github.com/mono/mono/blob/09ae7f243df64f6928ffcd89eb44ac1f688c689e/mono/metadata/sgen-gc.c > > it's instrumented to count how many times it repeats the Ephemeron scan, so > it probably wouldn't be too hard to get practical data on how expensive it is > in real usage.
We have a patch in progress for SpiderMonkey, in this bug: https://bugzilla.mozilla.org/show_bug.cgi?id=547941 It won't be in Firefox 4. Instrumentation is easy, the hard part (as ever) is workload selection. That would be good to build up, in advance of implementations. /be _______________________________________________ es-discuss mailing list es-discuss@mozilla.org https://mail.mozilla.org/listinfo/es-discuss
