Filip Andrei Reporter
	Description • 7 years ago

Name: Firefox
Version: 55.0a1
Windows 10 64 bit
buildID: 20170508030204

Steps to reproduce:
1. Launch browser.
2. Fill amazon.com in Navigation Start, then press enter.
3. Search "Lord of the rings"
4. Scroll down and access a non add results
5. Play  movie Trailer
6. Click back button
7. Record with Gecko Profile:(only the second access is captured)
8. Click on the second non-ad result: book
9. Capture profile.
10. Share the profile.


Profile
https://perfht.ml/2q5o47r

	Ionut Budeanu
	Comment 1 • 7 years ago

This Profile was recorded with the Acer hardware.

Name: Firefox
Version: 55.0a1
Windows 10 64 bit
buildID: 20170518030213


Steps to reproduce:
1. Launch browser.
2. Fill amazon.com in Navigation Start, then press enter.
3. Search "Lord of the rings"
4. Scroll down and access a non add results
5. Play  movie Trailer
6. Click back button
7. Record with Gecko Profile:(only the second access is captured)
8. Click on the second non-ad result: book
9. Capture profile.
10. Share the profile.


 
Gecko Profile: https://perfht.ml/2q0ykwA

	Jean Gong :jgong
	Comment 2 • 7 years ago

Sotaro, Please do an analysis of the profile in comment 1. Thanks!

	Sotaro Ikeda [:sotaro]
	Comment 3 • 7 years ago

I checked the profile, but I could not find useful information:( The context of the bug is not clear yet for me. Filip Andrei, can you answer the following questions?

- How slow was it to load the search result?
- What was your pc to test?
- The loading is slow without profiling(without step 7 ,9 and 10 in comment 0)?
- Does the problem happens without "5. Play  movie Trailer"in comment 0?
- Does the problem happens with another pcs?
- Does the problem happens with Firefox 54 and Firefox 56?

	Sotaro Ikeda [:sotaro]
	Comment 4 • 7 years ago

In profile in comment 1, there are long(563.88ms) event processing delay on tab thread. During it, content 2 main thread seemed very busy for re-styling and reflow.

	Filip Andrei Reporter
	Comment 5 • 7 years ago

Hi Sotaro,


Each week we run a benchmark test and we compare browser responsiveness between Firefox and Chrome and the procedure is to log bugs and gather profiles for all the scenarios that are slower than Chrome  according to release criteria .Benchmark is runned only on the latest nightly build and we have a tracked history that you can find here https://docs.google.com/spreadsheets/d/1UMsy_sZkdgtElr2buwRtABuyA3GY6wNK_pfF01c890A/edit?ts=58fd8bae#gid=1467038243 .

What was your pc to test?
Reference System:Acer Aspire E

	Sotaro Ikeda [:sotaro]
	Comment 6 • 7 years ago

(In reply to Filip Andrei from comment #5)
> 
> What was your pc to test?
> Reference System:Acer Aspire E

I used Lenovo P90.

	Sotaro Ikeda [:sotaro]
	Comment 7 • 7 years ago

(In reply to Sotaro Ikeda [:sotaro] from comment #4)
> In profile in comment 1, there are long(563.88ms) event processing delay on
> tab thread. During it, content 2 main thread seemed very busy for re-styling
> and reflow.

From the profile, I did not find the problem around graphics.

	Bobby Chien
	Comment 8 • 7 years ago

Hi Jonathan, could you help to follow Sotaro's investigation from comment 4? Thanks.

	Jonathan Kew [:jfkthame]
	Comment 9 • 7 years ago

It looks like style computation is taking a lot of time here; particularly RuleHash::EnumerateAllRules seems to stand out. :heycam, is this something where Stylo will likely help us out?

	Cameron McCormack (:heycam)
	Comment 10 • 7 years ago

Yes, EnumerateRules is basically the top level function of selector matching.  It looks like the profile is restyling big subtrees, which is Stylo's forte.

	Jonathan Kew [:jfkthame]
	Comment 11 • 7 years ago

Filip, can you re-test this with a current Nightly with stylo enabled, and see if there has been a useful improvement? Thanks.

	Ionut Budeanu
	Comment 12 • 7 years ago

Hi Jonathan!

Filip is on PTO for 2 weeks. In this case I provided a new gecko profile that you can find it below.

This test was performed with Stylo enabled and from what I saw the old profile is pretty much the same as the new one.   

This Profile was recorded with the Acer hardware.

Name: Firefox
Version: 57.0a1
Windows 10 64 bit
buildID: 20170808114032

Steps to reproduce:
1. Launch browser.
2. Fill amazon.com in Navigation Start, then press enter.
3. Search "Lord of the rings"
4. Scroll down and access a non add results
5. Play  movie Trailer
6. Click back button
7. Record with Gecko Profile:(only the second access is captured)
8. Click on the second non-ad result: book
9. Capture profile.
10. Share the profile.


 
Gecko Profile: https://perfht.ml/2fsM5UM

	Bobby Chien
	Comment 13 • 7 years ago

Hi Jonathan, could you help the profiling? Thanks.

	Jonathan Kew [:jfkthame]
	Comment 14 • 7 years ago

AFAICS, the main thing going on here is that a lot of JS is running, and doing things that trigger layout flushes (typically by accessing properties like offsetWidth and scrollWidth of elements).

https://perf-html.io/public/e71bccc5083db12300fdc43d39d15483dd5d7eeb/calltree/?hiddenThreads=2-3-4-1-0&search=flushpendingnotifications%20layout&thread=5&threadOrder=0-2-3-5-1-4

So if we could somehow avoid flushing layout so frequently, I think we could gain a lot here. But I'm not sure whether/how we can do that... we don't control what the page JS is doing, and if it keeps dirtying stuff and then querying layout-dependent properties, we lose. :(

	Jean Gong :jgong
	Comment 15 • 7 years ago

Moving this off to next round of Quantum Performance fixing for further investigation.

	Jean Gong :jgong
	Comment 16 • 6 years ago

Andrew, please investigate this bug further. Thanks!

	Andrew Creskey [:acreskey]
	Comment 17 • 6 years ago

On the 2017 reference laptop (Core i3, 2.4 GHz) I'm not able to reproduce any performance issues loading Amazon search results.

Testing on Firefox Nightly 66 (2018-12-13).

I also tried selecting search results, watching the trailer (as the bug was initially logged), and selecting more results: no noticeable performance problems were found.

Suggest closing this one.