1814841 - WebAssembly [dosbox-x] with exception-handling terrible performace comparing to other browsers

Status: RESOLVED FIXED

(Core :: JavaScript: WebAssembly, defect, P3)

Description

[caiiiycuk]

Attachment: ff-dosbox-x-perf.zip

User Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:109.0) Gecko/20100101 Firefox/109.0

Steps to reproduce:

Hi, I am author a js-dos project. I am ported dosbox-x to web assembly, it's core uses exception-handling feature of webassembly. To estimate performance I have a test dos program that I run inside emulator. This test reports an a VAX number.
I attached the zip with test page. Just press "Start direct" or "Start in worker" to start test. After some amount of time (like 20-30sec) test will print the report, like this:

0: 80000 runs, browser time 1275.300000 ms, VAX rating 35.703095
0: sleep p/sec 58 , avg cycles p/ms: 32030

"VAX" - is a test result, and "avg cycles p/ms" - how many emulation cycles did the browser perform.

Actual results:

When I run this test on FF 109, 110.0b8, the performance is really terrible, like
VAX - 0.14, avg cycles p/ms - 113
Evenmore from time to time "unreachable executed" is throwed (should not happen!)

Expected results:

On same PC results for other browsers:
Chrome:
VAX - ~35, avg cycles p/ms ~32000
Safari:
VAX - ~20, avg cycles p/ms ~19000

If I run simmilar core without eh, the results for firefox is VAX 50-70, so I am guessing that it's related to exception handling feature.

Comment 1

[BugBot [:suhaib / :marco/ :calixte]]

The severity field is not set for this bug.
:rhunt, could you have a look please?

For more information, please visit auto_nag documentation.

Comment 2

[Julien Pages [:jpages]]

Attachment: Profiling file

Profile captured on Linux x86 and Firefox 110.0.

Comment 3

[Julien Pages [:jpages]]

I can reproduce on Linux x86_64 and Firefox 110. I had to run a local http server to test this page.

With Firefox:

0: 10000 runs, browser time 10673.000000 ms, VAX rating 0.533263
0: sleep p/sec 61 , avg cycles p/ms: 411

0: 10000 runs, browser time 9601.000000 ms, VAX rating 0.592805
0: sleep p/sec 62 , avg cycles p/ms: 425

With Chrome:

0: 10000 runs, browser time 720.900000 ms, VAX rating 7.895020
0: sleep p/sec 63 , avg cycles p/ms: 3360

A profile is attached for the firefox run.

Comment 4

[Yury Delendik (:yury)]

After applying patch from bug 1837686, the results are about the same between FF and Chrome.

Comment 5

[Ryan Hunt [:rhunt]]

Resolving as fixed from bug 1837686.