577036 - JM: Make the code pattern dromaeo uses fast

Status: RESOLVED FIXED

(Core :: JavaScript Engine, defect)

Description

[Boris Zbarsky [:bzbarsky]]

The microbenchmark in bug 576926 comment 0 more or less measures dromaeo test overhead.  With the fixes in that bug, the benchmark is about 3x slower in JM than in TM, and about 5x slower than in v8.

We should try to make this fast if we can.

Comment 1

[Ryan VanderMeulen [:RyanVM]]

Interp: 294
JM: 3033
JM+TI: 14466
d8: 18358

JM+TI has mostly closed the performance gap with the bug 576926 comment #0 testcase, but not completely.

Comment 2

[Jan de Mooij [:jandem]]

We're faster than V8 now:

Interp   :   435
d8       : 24941
JM+TI    : 32314
Ion      : 39537

Pretty sure this is Luke's aliased var work, and IonMonkey adds another 7000 runs per second. Nothing to do here.

Comment 3

[Boris Zbarsky [:bzbarsky]]

Awesome, thanks!