1926314 - Measure impact of URL Classifier on geckoview startup

Status: NEW

(GeckoView :: General, task, P1)

Description

[Andrew Creskey [:acreskey]]

In this simpleperf profile, https://share.firefox.dev/4hgVLMd, we see a non-trivial amount of time spent in the URL Classifier thread during a Fenix startup.

It's not clear to what degree, if any, URL Classifier impacts Fenix startup, and if there are opportunities for improvements.

I tried disabling the underlying Safebrowing system and have not seen any improvements to startup time via the new shopify-applink-startup test.

This performance compare disables Safebrowsing, no measurable improvement.

This one further disables all tracking protection and channel annotation, no measurable improvement.

Comment 1

[Andrew Creskey [:acreskey]]

In bug 1927538 I measured a series of pageload visual metric and network timing improvements from simply disabling URL Classification.

To see if there was a performance impact on Fenix startup I made the same change, making NS_ShouldClassifyChannel() return false.

However no measurable improvement was found:
https://perf.compare/compare-results?baseRev=23eb6639c65309a3786eb9a5feb33697131774e4&baseRepo=try&newRev=4ad4738c7e9d94f42c43e0c66e649dd288760012&newRepo=try&framework=15

Comment 2

[Andrew Creskey [:acreskey]]

Hi Dimi,
I'm trying to evaluate the performance impact, if any, of Safebrowsing and URL Classification on Fenix startup.
Can you confirm that what I've done this this patch is sufficient to disable safebrowsing. i.e. disable any work that could potentially be in the critical path of startup?

Comment 3

[Dimi Lee [:dimi]]

(In reply to Andrew Creskey [:acreskey] from comment #2)

Hi Dimi,
I'm trying to evaluate the performance impact, if any, of Safebrowsing and URL Classification on Fenix startup.
Can you confirm that what I've done this this patch is sufficient to disable safebrowsing. i.e. disable any work that could potentially be in the critical path of startup?

Hi Andrew,
The patch only disables Phishing Protection, it doesn't disable anti-tracking related features.
I'd suggest setting the following preferences to empty:
https://searchfox.org/mozilla-central/search?q=updateURL&path=all.js&case=false&regexp=false
https://searchfox.org/mozilla-central/search?q=gethashURL&path=all.js&case=false&regexp=false

Comment 4

[Andrew Creskey [:acreskey]]

Thanks Dimi,

I had a chance to run this and it's picking up a low-confidence 4.3% improvement from disabling these features. But with very high noise (20% std deviation), so very much to be taken as low confidence.
Performance Compare

As the startup test results are currently bimodal, ranging from 1800ms to over 5000ms, I think it will be difficult to meaningfully evaluate the impact of the URL classifier until bug 1923443 is fixed.

Geckoprofiles would help, so will try to get more.