1182906 - Horrible jank when scrolling about:healthreport's Raw Data

Status: RESOLVED WORKSFORME

(Firefox :: Untriaged, defect)

Description

[Mikel]

User Agent: Mozilla/5.0 (Windows NT 6.3; WOW64; rv:42.0) Gecko/20100101 Firefox/42.0
Build ID: 20150711030210

Steps to reproduce:

1) Enter about:healthreport
2) Click on "Raw Data"
3) Scroll the page - horrible jank.


Actual results:

Horrible stutters and jank while scrolling the page.


Expected results:

Smooth scrolling of the page.

Comment 1

[Benjamin Smedberg]

Not a core part of the content perf requirements, but bad testcases are always worth investigation.

Are there any other tabs open when this scrolling is a problem, or is it only about:healthreport?

Mikel, would you be interested in capturing a profile using a Firefox nightly build and the gecko profiler? https://developer.mozilla.org/en-US/docs/Mozilla/Performance/Profiling_with_the_Built-in_Profiler has instructions.

BenWa, since the "jank-only" mode of the profiler is gone, what's the best technique to use the profiler to debug a jank problem?

Comment 2

[Mikel]

bsmedberg, is there a known issue with Gecko profiler?
I don't seems to be able to load/analyze the profile after recording it (it gets stuck with "Retrieving profile" with no movement..) :/

Comment 3

[Benjamin Smedberg]

I don't know, I'm going to just redirect that question to bgirard as well.

Comment 4

[Benoit Girard (:BenWa)]

(In reply to Benjamin Smedberg  [:bsmedberg] from comment #1)
> BenWa, since the "jank-only" mode of the profiler is gone, what's the best
> technique to use the profiler to debug a jank problem?

There 'jank-only' was really meant for this type of use case anyways.

You should be able to get the information you want by analyzing the timeline and the activity during the gaps in the 'Frames' view during scrolling.

(In reply to Mikel from comment #2)
> bsmedberg, is there a known issue with Gecko profiler?
> I don't seems to be able to load/analyze the profile after recording it (it
> gets stuck with "Retrieving profile" with no movement..) :/

There's a known regression with the JS intstrumentation causing it to crash but I'm not aware of any bugs causing the profile to fail to retrieve. This should be filed with STR against 'Gecko Profiler'.

Comment 5

[Benoit Girard (:BenWa)]

Attachment: Screenshot 2015-07-13 14.44.50.png

Here's my profile:
http://people.mozilla.org/~bgirard/cleopatra/#report=6ceec99c1d11ce085737a594208c63c345cb2dc4&filter=[{"type"%3A"RangeSampleFilter","start"%3A6288962,"end"%3A6289922}]

I've also attach a screenshot of the profile. Frames are pretty closely clustered around 16.6ms.

However is looks like the nearly all the time is spent in the Display List phase. Someone experiencing the jank should post their profile but it might be that with more data/text the 'Display List' phases likely goes out of budget.

Comment 6

[Mikel]

Hmm...

well, if I record a profile *without* GPU and Power compartments ticked I get the following popup:

"Could not connect to symbolication server at http://symbolapi.mozilla.org/gecko-profiler/
Please verify that you are connected to the Internet."

Anyhow, here is the profile without these categories:
https://people.mozilla.org/~bgirard/cleopatra/#report=e345e718bc4ac918b1a73092407096ca7392472c

*Note: With a new profile the scrolling is smooth.. so I have recorded this on my dirty profile..

Is this sufficient?

Comment 7

[Benoit Girard (:BenWa)]

The reason your profiles don't always work is probably because you've set profiler.entries too high. You're also running with 8 content processes.

I'd suggest not changing the default unless you're looking for that data in particular, and then removing that option after you've collected the profile.

Try grabbing a new profile with e10s disabled.

The server at 'http://symbolapi.mozilla.org/gecko-profiler/' should be working I'm told.

Comment 8

[Mikel]

Well, I don't remember touching profiler.entries, but I will get this back to the default Preset from the settings and record a new profile with e10s disabled..

And the symbolapi.mozilla.org seems to not be available (http://downforeveryoneorjustme.com/symbolapi.mozilla.org/gecko-profiler/)

Attaching a profile with e10s disabled (and still with GPU and Power disabled after changing the profiler.entries to default value):
https://people.mozilla.org/~bgirard/cleopatra/#report=02bc9e766e9235f902ea2fabb0c09d864e48d06f

Comment 9

[Benoit Girard (:BenWa)]

Your frame rates seems to jump between 60 FPS and 30 FPS but otherwise I don't see anything wrong with this profile.

Comment 10

[Mikel]

So this is why I see the scrolling very stuttery?
Also, as I have mentioned, there are no stutters if I create a new profile and scroll there...

Comment 11

[Mikel]

WFM after closing the tab with http://www.securitytube.net.
See bug 1220498 for more details.

Not sure yet if bug 1197648 is relevant to this or not.