1169950 - Firefox is slower than Chrome on Massive-poppler-cold-preparation

Status: NEW

(Core :: JavaScript Engine, defect)

Description

[Guilherme Lima]

My scores (win7):

Firefox 38 - 223
Nightly 41 - 220
Chrome 43 - 628

I'm only filling this bug because this is the only test where Chrome beats Firefox on Massive Benchmark.

Comment 1

[Alon Zakai (:azakai)]

This is expected. cold-preparation tests measure startup times without anything in the cache. Firefox does AOT compilation of asm.js code, which lets it run faster later, but it does have a startup cost. Chrome JITs the code with far fewer optimizations, but it does so more quickly.

It might still be worth looking at the AOT times, though, for anything to optimize.

Comment 2

[Emanuel Hoogeveen [:ehoogeveen]]

I imagine bug 1169167 could help a lot here.

Comment 3

[Luke Wagner [:luke]]

Yes, I'm not totally familiar with the TurboAsm compilation strategy, but iirc, it doesn't compile *fully* AOT, just AOT-er.  Does cold-prep run *any* code or purely just load the script?

Comment 4

[Alon Zakai (:azakai)]

main() is not run, so essentially no code executes, just parsing/compilation and emscripten setup until main() is ready to be called (including global constructors, but no big ones there).