1864392 - Honor `fetchpriority` attribute for HTTP/3 requests

Status: RESOLVED FIXED

(Core :: Networking: HTTP, task, P2)

Description

[Mirko Brodesser (:mbrodesser-Igalia)]

HTTP/3 requests use the mapping of the class of service at https://searchfox.org/mozilla-central/rev/40d51bef58b8e901d6ab4b60dd280f372a0e417d/netwerk/protocol/http/Http3Stream.cpp#83-106 to determine their priority.

See https://searchfox.org/mozilla-central/rev/fe8b30e982c86d26ccf1f14d825c0de870b91f27/modules/libpref/init/StaticPrefList.yaml#12397-12399 for a link to the extensible prioritization scheme for HTTP used by HTTP/3 in Gecko.

However, the fetchpriority attribute currently only affects nsISupportsPriority, see e.g. https://searchfox.org/mozilla-central/rev/fe8b30e982c86d26ccf1f14d825c0de870b91f27/dom/script/ScriptLoader.cpp#692,698, not the class of service mentioned above.

Hence, fetch priority currently doesn't affect HTTP/3 requests.

Comment 1

[Valentin Gosu [:valentin] (he/him)]

We currently send a priority update only when the window of the request becomes active/inactive:
https://searchfox.org/mozilla-central/rev/fe8b30e982c86d26ccf1f14d825c0de870b91f27/netwerk/protocol/http/Http3Stream.cpp#158

We should make sure to consider the fetchpriority when sending the update, and also when issuing the initial request here
https://searchfox.org/mozilla-central/rev/fe8b30e982c86d26ccf1f14d825c0de870b91f27/netwerk/protocol/http/Http3Session.cpp#1157

Comment 2

[Mirko Brodesser (:mbrodesser-Igalia)]

Presumably the initial version of fetchpriority can ship without this.

Comment 4

[Valentin Gosu [:valentin] (he/him)]

Attachment: Bug 1864392 - Adjust HTTP urgency based on fetchpriority/nsISupportsPriority value r=#necko

Comment 5

[BugBot [:suhaib / :marco/ :calixte]]

There is an r+ patch which didn't land and no activity in this bug for 2 weeks.
:valentin, could you have a look please?
If you still have some work to do, you can add an action "Plan Changes" in Phabricator.
For more information, please visit BugBot documentation.

Comment 6

[Valentin Gosu [:valentin] (he/him)]

Will land this week.

Comment 7

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/779d7dc63e81
Adjust HTTP urgency based on fetchpriority/nsISupportsPriority value r=necko-reviewers,jesup

Comment 8

[Pulsebot]

Backout by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/0b9c89f96c25
Backed out changeset 779d7dc63e81 for causing mochitest failures on browser_net_copy_headers.js

Comment 9

[Aron Cseh]

Backed out for causing mochitest failures on browser_net_copy_headers.js

• Backout link
• Push with failures
• Failure Log

Comment 10

[Frédéric Wang (:fredw)]

(In reply to Aron Cseh from comment #9)

Backed out for causing mochitest failures on browser_net_copy_headers.js

• Backout link
• Push with failures
• Failure Log

The test expects u=1 at https://searchfox.org/mozilla-central/rev/ccb101be8f27d837b655ccee51a52c0337dd1eb8/devtools/client/netmonitor/test/browser_net_copy_headers.js#50 but with the patch it gets u=0.

Comment 11

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/e19c8f1d3cf7
Adjust HTTP urgency based on fetchpriority/nsISupportsPriority value r=necko-reviewers,jesup,devtools-reviewers

Comment 12

[Atila Butkovits]

https://hg.mozilla.org/mozilla-central/rev/e19c8f1d3cf7