1146361 - (iosstartuptime) [meta] Improve startup time

Status: RESOLVED FIXED

(Firefox for iOS :: General, defect)

Description

[Mark Finkle (:mfinkle) (use needinfo?)]

We should start profiling parts of the application, like startup. The orange startup splash displays for an uncomfortably long amount of time.

Using 2014 iPod running iOS 8.2

Comment 1

[Aaron Train [:aaronmt]]

Attachment: iPhone6-time-profiler.trace.zip

Time Profiler from my iPhone 6, not that bad ~330ms with +~100ms in TabManager code

Comment 2

[Stefan Arentz | :st3fan | ⏰ EST | he/him]

Aaron can you measure again and see if things improved?

Comment 3

[Aaron Train [:aaronmt]]

No improvement. Finkle can check his iPod again.

Comment 4

[Aaron Train [:aaronmt]]

Attachment: startup.trace.zip

Build #9 startup, iPhone 6 (8.3)

Measured time from launch (suspended) through splash-screen to idle on about:home

Comment 5

[Stefan Arentz | :st3fan | ⏰ EST | he/him]

Suggestion to shave of ~ 90ms

Every time at app startup we create a UIWebView to get the User Agent and then modify it to include our own unique string. This is an expensive operation. We can assume that the User Agent only changes as part of an iOS upgrade so we should remember the current iOS version and user agent, compare the iOS version and skip the UIWebView creation if it is the same.

Comment 6

[Stefan Arentz | :st3fan | ⏰ EST | he/him]

Suggestion to shave off 100s of ms

When we restore your tabs, we ask the TabManager to create new tabs with a specific NSURL. This immediately creates a WKWebView instance. This is an extremely expensive operation. The more tabs people have open, the worse this gets. We should only fully restore the front tab. And restore the others lazily when they are opened.

Comment 7

[Stefan Arentz | :st3fan | ⏰ EST | he/him]

Suggestion to shave off ~ 100ms

BrowserViewController.viewDidLoad() takes about 200 ms. Half of that is the creation of the ReaderModeBarView. We should to create that view lazily when it is needed. Not always at app startup.

Comment 8

[Wesley Johnston (:wesj)]

Can you file bugs for those things (and link them against this)?

Comment 9

[Stefan Arentz | :st3fan | ⏰ EST | he/him]

In BrowserViewController.viewDidLoad we create a new tab if no tabs were restored. This tab will initially open with the home screen.

Two things:

Can we create the WKWebView for this tab lazily until the user opens a link?

I think in BVC.animateToolbarsWithOffsets() we call layoutIfNeeded() twice:

        self.view.layoutIfNeeded()
        if animated {
            UIView.animateWithDuration(duration, animations: animation, completion: completion)
        } else {
            animation()
        }

Can the above call to layoutIfNeeded() be moved into the 'if animated' block? I don't think it is needed if no animations are run?

Comment 10

[Stefan Arentz | :st3fan | ⏰ EST | he/him]

I have been testing on an iPhone 6 and iPhone 5. Both are pretty fast. Like, a cold boot takes ~1.25 seconds. I would like to understand on what kind of device it takes many seconds to start.

Comment 11

[Wesley Johnston (:wesj)]

Untracking the meta bug.