1239314 - Consider turning off incremental marking validation

Status: RESOLVED FIXED

(Core :: JavaScript: GC, defect)

Description

[Jon Coppeard (:jonco) (Away until 30th Nov)]

nical says that GC takes 25% of time in debug reftests, and could be a big factor in the number of test timeouts.

Incremental marking validation is something that happens in all debug GCs, but hasn't caught any bugs in as long as I can remember.

What do you think about turning this off by default and adding a zeal mode to enable it if we do want to run it?

I suppose we should measure how much this speeds up reftests first.

Comment 1

[Nicolas Silva [:nical]]

This number comes from the first five to ten minutesof the reftest suite with a local debug build on two of my laptops. I'm not sure how much that is on actual try runs but it's worth investigating. On a very beefy desktop the same GC symbols are still getting the biggest scores although they tend to have lower percentages.

Comment 2

[Terrence Cole [:terrence]]

Attachment: make_marking_validation_a_zeal_mode-v0.diff

I strongly agree. Let's recycle mode 11.

Comment 3

[Jon Coppeard (:jonco) (Away until 30th Nov)]

Comment on attachment 8707594 [details] [diff] [review]
make_marking_validation_a_zeal_mode-v0.diff

Review of attachment 8707594 [details] [diff] [review]:
-----------------------------------------------------------------

Great!

::: js/src/builtin/TestingFunctions.cpp
@@ +788,5 @@
>          ReportUsageError(cx, callee, "Wrong number of arguments");
>          return false;
>      }
>  
> +    JS_SetGCZeal(cx, 11, 0);

This needs to enable / disable validation based on the first argument.

Comment 4

[Terrence Cole [:terrence]]

https://treeherder.mozilla.org/#/jobs?repo=try&revision=4257bd7b0039

Comment 5

[Terrence Cole [:terrence]]

https://treeherder.mozilla.org/#/jobs?repo=try&revision=7655f1d92370

Comment 6

[Terrence Cole [:terrence]]

https://hg.mozilla.org/integration/mozilla-inbound/rev/a048c55e1906f380a9f95d8f1dfa8308c37629cd
Bug 1239314 - Make marking validation a normal zeal mode; r=jonco

Comment 7

[Phil Ringnalda (:philor)]

https://hg.mozilla.org/mozilla-central/rev/a048c55e1906