Bug 161436 – stress/random-53bit.js.ftl-no-cjit-no-inline-validate sometimes fails

• Status: RESOLVED
• Resolution: FIXED
• Component: JavaScriptCore

[Filip Pizlo]

I think this failure is rare.  It doesn't happen all the time because it probably depends on a particular return value from Math.random().

[Filip Pizlo]

This is all it says when it fails:

stress/random-53bit.js.ftl-no-cjit-no-inline-validate: Exception: Error: OUT
stress/random-53bit.js.ftl-no-cjit-no-inline-validate: global [e-mail]:23:24
stress/random-53bit.js.ftl-no-cjit-no-inline-validate: ERROR: Unexpected exit code: 3

[Yusuke Suzuki]

Ooooops, thanks. Looking.

[Yusuke Suzuki]

I think there are two possible reasons.

1.
By design, this test rarely may fail.
We can reduce this rate by increasing MAX value.
It may solve the issue.

2.
It may be caused by the specific random seed patterns.


If (1) is the reason, everything is ok. We can just increase the MAX value.
But if (2) is the reason, there should be some issues.
To validate the reason, I'm infinitely executing this test now.

[Yusuke Suzuki]

Reproduced. Failed pattern is the following.

https://gist.github.com/Constellation/0f43a235e6e43bfc9ab7ddc4a537757a

And I'll dump the random seed...

[Yusuke Suzuki]

OK, this is just because accidentally some random sequence is shown.
I'll tweak the test to reduce this rate.

[Yusuke Suzuki]

Created attachment 287526 [details]
Patch

[Filip Pizlo]

Comment on attachment 287526 [details]
Patch

View in context: https://bugs.webkit.org/attachment.cgi?id=287526&action=review

> JSTests/stress/random-53bit.js:25
> -for (var i = 0; i < 1e4; ++i) {
> +for (var i = 0; i < 1e2; ++i) {

I don't think this is a good idea.  Eager tests mean that they compile with less profiling, which may lead the compiler to make different decisions.  I've only seen this fail in a non-eager config, and I don't think you can be sure that an eager test would catch a non-eager failure.

[Yusuke Suzuki]

Comment on attachment 287526 [details]
Patch

View in context: https://bugs.webkit.org/attachment.cgi?id=287526&action=review

>> JSTests/stress/random-53bit.js:25
>> +for (var i = 0; i < 1e2; ++i) {
> 
> I don't think this is a good idea.  Eager tests mean that they compile with less profiling, which may lead the compiler to make different decisions.  I've only seen this fail in a non-eager config, and I don't think you can be sure that an eager test would catch a non-eager failure.

Make sense.
Just increasing the MAX value should solve the problem.

[Yusuke Suzuki]

Created attachment 287529 [details]
Patch

[WebKit Commit Bot]

Comment on attachment 287529 [details]
Patch

Clearing flags on attachment: 287529

Committed r205267: <http://trac.webkit.org/changeset/205267>

[WebKit Commit Bot]

All reviewed patches have been landed.  Closing bug.