539989 - Object visualization tool

Status: RESOLVED INACTIVE

(Core :: JavaScript Engine, enhancement)

Description

[Gregor Wagner [:gwagner]]

Since we want to test several GC strategies for JS and identify bottleneck of the current GC, we should have some kind of visualization tool. The idea is to generate heap snapshots before/after a GC and write this (maybe filtered) information to a file. Visualization tools that read XML files are around. Visualization properties could be age, arena group, connections....

Comment 1

[Brendan Eich [:brendan]]

JSON >> XML for such things...

/be

Comment 2

[Ryan VanderMeulen [:RyanVM]]

Is this still relevant as a non-TM bug?

Comment 3

[Nicholas Nethercote [inactive]]

(In reply to Ryan VanderMeulen from comment #2)
> Is this still relevant as a non-TM bug?

Yes, though I don't see it going anywhere soon.  Gregor, want to close it?

Comment 4

[Andrew McCreight [:mccr8]]

With bug 680482, we can dump a textual representation of the GC heap.  It shouldn't be too hard to modify my CC heap visualization script to do the same for GC, but that is fairly crude, so I'm not sure if you could do anything about age or arena groups.

Comment 5

[Gregor Wagner [:gwagner]]

We have an outdated implementation but we might rebase it.

Comment 6

[David Bruant]

At JSConf.eu, I have seen such a tool being used during Erik Corry's presentation (from the Chrome team). So such a tool already exists and it may be a matter of feeding its API. I don't know where it is though.

Changing the summury, because if you want a tool to visualize objects, it's a different thing. (I have started one at http://davidbruant.github.com/ObjectViz/ )

Comment 7

[Nicholas Nethercote [inactive]]

With the renaming of this bug it looks awfully similar to bug 670594.  That one has some old code, it was for visualizing at a very high level -- chunks and arenas.  Sounds like this bug is about more fine-grained visualization.  The names should be changed to reflect this.

Comment 8

[Gregor Wagner [:gwagner]]

Nick already has a bug about heap visualization. This bug is about a finer granularity where we can look at individual objects.

Comment 9

[BugBot [:suhaib / :marco/ :calixte]]

The bug assignee didn't login in Bugzilla in the last 7 months.
:sdetar, could you have a look please?
For more information, please visit auto_nag documentation.

Comment 10

[Steve Fink [:sfink] [:s:]]

• mccr8's tools contain scripts for processing the GC heap dump now, in addition to the CC heap dump tools. I don't think there's anything for visualization, though.
• The Memory tab in devtools has a rather nice display of the various types of objects in the heap, though it seems pretty limited in interaction, filtering, etc.
• about:memory serves some part of this need.
• we have various profiling output that dumps out some information

The intent of this bug seems to be more about something that would help tune the GC. We still have that need. Whether a visualization tool would be an important part of that, I'm not sure.

Closing. If we decide we need something like this, it'd probably be better to start a new bug. The information in the comments here is stale.