1907364 - ProxyResolution thread can use significant CPU on high request documents

Status: RESOLVED FIXED

(Core :: Networking: Proxy, enhancement, P2)

Description

[Andrew Creskey [:acreskey]]

It was observed in Bug 1904284 that we can spend a lot of CPU cycles in the ProxyResolution thread if there are a lot of requests.

Profile: https://share.firefox.dev/4bGMGZk

Kershaw suggest that we could optimize this as we did in bug 1392272 (reverted in bug 1749501):

However, I do see an opportunity here. From the all-thread sample, I notice that the ProxyResolution thread uses ~30% CPU resources. I think it would be beneficial to revisit bug 1392272 (which was reverted in bug 1749501) to avoid reading system proxy settings for every HTTP request.

Comment 1

[Kershaw Chang [:kershaw]]

The initial patch in bug 1392272 was backed out because it didn’t handle the proxy exception list correctly.
The first step would be to add a test to ensure that future changes don’t cause regressions.
I plan to work on this bug soon.

Comment 2

[Kershaw Chang [:kershaw]]

Attachment: Bug 1907364 - Cache system proxy config on Android, r=#necko

Previously, we called the Android system proxy API via JNI for every new request.
With this change, the proxy config is cached, allowing us to reuse the result and avoid repeated JNI calls.

Comment 3

[Kershaw Chang [:kershaw]]

Attachment: Bug 1907364 - Add network.proxy.detect_system_proxy_changes to Android nimbus manifest, r=#necko

Comment 4

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/7d26bbeb5528
Cache system proxy config on Android, r=necko-reviewers,geckoview-reviewers,valentin,m_kato

Comment 5

[Andrew Creskey [:acreskey]]

I compared this patch again on the newssite-applink-startup applink_startup (without profiling runs) but it did not pick up any improvements.

https://perf.compare/compare-results?baseRev=77ac96ad1ce81db0107b8ab6082b147499eeb01b&newRev=ab24cf5ecd088c311a3f2f14a709d8271822a53a&baseRepo=try&newRepo=try&framework=15

Comment 6

[Norisz Fay [:noriszfay]]

https://hg.mozilla.org/mozilla-central/rev/7d26bbeb5528