1358291 - LinkedIn loads 2+ sec slower on Firefox compared to Chrome

Status: RESOLVED WORKSFORME

(Core :: General, defect)

Description

[:Harald Kirschner :digitarald]

Steps:

- Log in
- Open https://www.linkedin.com/feed/ (or https://www.linkedin.com/in/digitarald/)

Pages load massively slower, over 2-3sec. This is confirmed by LinkedIn contacts.

Profile on Mac/Nightly collected while navigating around the page: https://perfht.ml/2pkgHv0

Comment 1

[:Harald Kirschner :digitarald]

The initial thought was that bug 1331680 causes most of the issue as LinkedIn read cookies 60+ times during page load. They fixed that and the cookie is read only once now but page load did not improve.

naveed, can we confirm that 2sec+ slowness is just JS issues with Ember?

Comment 2

[:Harald Kirschner :digitarald]

[Tracking Requested - why for this release]:
Slow page load reported by users and confirmed by LinkedIn.

Comment 3

[Steve Fink [:sfink] [:s:]]

I can see the slowness, but I couldn't tell much from the profile. Although some of the JS function names were kind of weird -- i.prototype.compile(), e.prototype.compileStatement(), t.prototype.evaluate(). Seems like there must be some processing engine running within JS?

evilpie, does your CacheIR dumper show anything interesting?

Comment 4

[Naveed Ihsanullah [:naveed]]

:sfink does TraceLogger give any other insight?

Comment 5

[Tom S [:evilpie]]

I don't see anything super bad and I also don't get 2s load times. Actually because we fallback to the generic stub now, it's not necessarily easy to tell. I really need to fix bug 1348821, but I don't have a good approach for it.

Some things that stood out to me: hasOwnProperty where the base is a primitive, in on an arguments object (both indexes and length) and SetElem with an index.

Btw: Running CacheIR is really simple now, just start Nightly with CACHEIR_LOGS=1.

Comment 6

[Liz Henry (:lizzard) (relman/hg->git project)]

Can you test with 55 or 54 rather than 53? I can also ask for QE help here. 

It seems unlikely we'll be fixing this for 53, though if you disagree, please let me know.

Comment 7

[Liz Henry (:lizzard) (relman/hg->git project)]

Tracking for 55 to make sure this doesn't get lost in the shuffle.

Comment 8

[Liz Henry (:lizzard) (relman/hg->git project)]

This did get lost. Andrei can your team have a look to see if this is still true? 
sfink, can you still see the perf issues at all?

Comment 9

[Ritu Kothari (:ritu) (Inactive, please n-i to RyanVM, jcristau, or pascal)]

I did a layman test on my win10 laptop and it is indeed 2-3 seconds slower to load linkedin.com/feed on Nightly56 as compared to Chrome v59

Comment 10

[Bogdan Maris, Desktop QA]

I could also see this in latest Nightly 56 compared with Chrome 59, Windows 10 64bit. So this is definitely still here. Please let me know if there is something I can help with here.

Comment 11

[:Harald Kirschner :digitarald]

This doesn't reproduce for me since Quantum, as both Firefox and LinkedIn changed substantially.