1702354 - Long pauses on some web pages, likely related to credit-card autofill ruleset

Status: VERIFIED FIXED

(Core :: Performance: General, defect)

Description

[B.J. Herbison]

Basic information

A web application I am developing started pausing for long periods of time recently. The JavaScript-generated page has a large number of text fields. Until recently the page would sometimes pause for a second or two the first or second time I clicked into one of the input fields. Using ASan Nightly recent versions can pause for up to a minute, regular Nightly can pause for 10-15 seconds.

Steps to Reproduce:

Open the page and click in a text field. If that is fast click in a second.

Expected Results:

No pause.

Actual Results:

Until recently, pauses for a second or two. Recently: long pauses. (Up to a minute with ASan Nightly, up to 15 seconds with Nightly.)

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More information

mozregression says this push caused the problem:
https://hg.mozilla.org/integration/autoland/pushloghtml?fromchange=1fd580d39fcf2f43742a5e2c70568e39eab9e039&tochange=7b19f4ed5182b81f3ec3f3dee1989d306c00f7e7

Profile URL: (follow the instructions at https://profiler.firefox.com/)

The profiles contain screenshots with information I don't want to release. Attached are two screen captures from profiler.firefox.com. Most of the one minute delay in the capture was inside two calls to getSubfactsFromFunction inside of fathom.jsm

I will try to generate a test case I can share.

Basic systems configuration:

OS version: Ubuntu 20.04.2 LTS

GPU model: Intel Corporation UHD Graphics 630 (Mobile)

Number of cores: 12

Amount of memory (RAM): 32GiB

Thanks so much for your help.

Comment 1

[B.J. Herbison]

Attachment: Profiler screenshot from the first part of the pause

Comment 2

[B.J. Herbison]

Attachment: Profiler screenshot from the second part of the pause

Comment 3

[B.J. Herbison]

Attachment: Lots of text fields

When I open the attached stuff.html in release I can click in text fields without delay. (With some other web pages with fewer text fields I've seen a few second delay on the first or second click.)

When I open the file in Nightly the first or second click in a text field causes a ten minute hang.

Comment 4

[B.J. Herbison]

When I used mozregression to find the problem code the delay wasn't happening at all with the profiles created by mozregression. But the delay is seen using fresh profiles created by the profile manager, and with mozregression when I told it to use the standard profile.

Comment 5

[Erik Rose [:erik][:erikrose]]

FWIW, it's the CreditCardRuleset.jsm used for credit-card autofill, not Fathom itself. We've backed out that ruleset till I can figure out the perf issue.

Comment 6

[Henrik Skupin [:whimboo][⌚️UTC+2]]

The regression should be fixed by the backout of bug 1681985.

Comment 7

[Giorgia Nichita, Release Desktop QA]

We've tried to reproduce the issue following the mentioned steps but I can click in the text fields without any delay. We used an affected Nightly (2021-03-28), as well as an asan Nightly (2021-03-30).

Can you please tell us if you can still reproduce this issue on latest Beta 89?

Comment 8

[B.J. Herbison]

I have not seen this issue since the backout mentioned in comment 6. I the page that previously caused problem almost daily with Nightly 89 after the backout and with Nightly 90 now.

Comment 9

[Markus Stange [:mstange]]

(In reply to Giorgia Nichita, Release Desktop QA from comment #7)

We've tried to reproduce the issue following the mentioned steps but I can click in the text fields without any delay.

It might be because of your region - see bug 1685798 comment 4 for details.

Comment 10

[Giorgia Nichita, Release Desktop QA]

I was able to reproduce the issue with browser.search.region on CA, on an affected Nightly build 2021-03-28, as well as on an asan Nightly (2021-03-30).

The fix was verified using the latest Nightly 90.0a1 (2021-05-11) and Firefox 89.0b11 (2021-05-11) on Ubuntu 20.04.
Thanks Markus for your help!