489136 - TM: No substantial speed increase

Status: RESOLVED DUPLICATE of bug 489146

(Core :: JavaScript Engine, defect)

Description

[Dannii]

User-Agent:       Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.0.8) Gecko/2009033100 Ubuntu/9.04 (jaunty) Firefox/3.0.8
Build Identifier: Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.1b4pre) Gecko/20090401 Ubuntu/9.04 (jaunty) Shiretoko/3.5b4pre

By profiling with Firebug enabling JIT seems to make no difference to the performance of this page.

Reproducible: Always

Steps to Reproduce:
Enter the three commands 'y', 'n', 'n'.


Expected Results:  
Some, if minimal, speed increase.

About 15% of the time is taken by eval() (in ge_run) which I wouldn't expect to be helped by the JIT.

The rest is just a lot of function calls, however most functions are quite short and straightforward. For example, ge_func_return: http://code.google.com/p/parchment/source/browse/trunk/gnusto-engine.js#2943

Comment 1

[Dannii]

Attachment: Logs from Firebug

Comment 2

[Sylvain Pasche]

JIT is not yet enabled for x86_64. See bug 489146.

I'm not completely sure, but having the Firebug profiler active may disable TM (Firebug activates the JavaScript debugger service which does not play well with TM IIRC).

It could be interesting if you try again with a 32bit build and maybe with Firebug off if it doesn't make a difference. That's always interesting to hear about TM performance improvements.