Bug 16448 – [GTK] Celtic Kane JavaScript performance on Array test is slow relative to Mac

• Component: JavaScriptCore
• Status: RESOLVED FIXED

[Alp Toker]

The GTK+ port takes an unexpectedly high time on the Celtic Kane "Array object" benchmark:

  http://celtickane.com/webdesign/jsspeed2007.php

wk 605ms
fx2 264ms

the DOM test is also suspiciously slow:

wk 261ms
fx2 179ms

Probably something silly going on. We need to throw a profiler at this.

[Mark Rowe (bdash)]

Grr, I spent a little while this evening trying to find a profiler on Linux that would give me understandable data but failed miserably.

[Mark Rowe (bdash)]

Finally got gprof working.  Most of the time looks to be spent inside toString in the comparison function below ArrayInstance::sort.  I have a patch locally that tweaks ArrayInstance::sort to call toString O(N) times rather than O(N log N) times, which drop the Array test from 158 to 7ms on my Linux machine.  I'm not entirely sure *why* toString was proving more expensive on Linux as gprof output isn't proving very enlightening. The patch is also a win on Mac (36 -> 6ms on Array).

[Mark Rowe (bdash)]

I'm not seeing the DOM test as being slow on my machine.  It consistently takes around 25ms.

[Mark Rowe (bdash)]

I'm re-titling this bug for now to cover the Array aspect for which I have a patch.  We should file separate bugs on other parts of the benchmark that are slower than expected.

[Mark Rowe (bdash)]

Created attachment 17939 [details]
Patch

[Maciej Stachowiak]

Comment on attachment 17939 [details]
Patch

r=me

[Maciej Stachowiak]

(But I suggested an improvement to the comment)

[Mark Rowe (bdash)]

Landed in r28782.