1177947 - Quick sort function not staying in ion

Status: RESOLVED INCOMPLETE

(Core :: JavaScript Engine: JIT, defect, P3)

Description

[Nick Fitzgerald [:fitzgen] [⏰PST; UTC-8]]

Attachment: Screen Shot 2015-06-26 at 2.33.52 PM.png

Test case: https://github.com/fitzgen/source-map/commit/c9807b8b5d4085a2aa9e912f819bb8e46fe4ed30

Clone repo:

    $ git clone https://github.com/fitzgen/source-map
    $ cd source-map
    $ git checkout c9807b8b5d4085a2aa9e912f819bb8e46fe4ed30

Make the concatenated build:

    $ npm install
    $ node Makefile.dryice.js # ignore "failed to find module" warnings

To repro from the shell:

    $ cd source-map/bench/
    $ $JS_SHELL ./bench-shell-bindings.js

Or within the browser:

* Navigate to file://path/to/source-map/bench/bench.html
* Click on "benchmark parsing source map"

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The quick sort function will often (but not always) stay in baseline for about 2/3 of its runtime. :djvj speculated that we enter quick sort in baseline, it gets hot enough for ion, when we recurse we compile it in ion without an entry point for any loop head, and then baseline frames down the stack never get to swap into ion.

Another idea was that we are doing shrinking GCs and throwing away type info and jit code, and then failing to get back into ion well.

Not really clear to me what's going on, but it seems like we should do better than this.

Comment 1

[Jan de Mooij [:jandem]]

Hm how do you get the view in the attached screenshot? I can see the JIT optimization stuff but where the graph is it's white and I've no idea how to change that.

Comment 2

[Kannan Vijayan [:djvj]]

I ran into the same issue.  There was a patch for this that I applied to get it showing the graph properly.  I had thought it'd be applied by now, but it might not be.

Nick, do you still have that patch you were using to get the optimization tier mountainrange view to show up properly?  Also is there a bug reference for that issue?

Comment 3

[Nick Fitzgerald [:fitzgen] [⏰PST; UTC-8]]

Bouncing this ni to Jordan, as I had thought this fix would have landed by now too, and am not sure where that patch went either.

Comment 4

[Jordan Santell [:jsantell] [@jsantell]]

Meta bug for "JIT View": https://bugzilla.mozilla.org/showdependencytree.cgi?id=1143804&hide_resolved=1

Optimization tier over time is bug 1150299, should be able to work on this soon again :[