Revert minimum pacer delay constraint

👁 Image	Max Inden Assignee
	Description • 1 year ago

https://phabricator.services.mozilla.com/D191325 introduced an optimization, practically speaking ignoring any pacer delay < 1ms.

Since then https://github.com/mozilla/neqo/pull/2035 fixed the underlying issue in Neqo itself.

I suggest removing the optimization in neqo_glue, see also past discussion, for the following reasons:

• reducing code duplication
• instead of messing with time, always provide accurate time (i.e. Instant::now) to Neqo

👁 Image	Max Inden Assignee
	Comment 1 • 1 year ago

👁 Image	Pulsebot
	Comment 2 • 1 year ago

Pushed by mail@max-inden.de: https://hg.mozilla.org/integration/autoland/rev/36d26905ef58 Revert minimum pacer delay constraint r=kershaw,leggert,necko-reviewers

👁 Image	Gregory Pappas [:gregp]
	Comment 3 • 1 year ago

These prefs are removed:

• network.http.http3.max_accumlated_time_ms

👁 Image	Sandor Molnar[:smolnar]
	Comment 4 • 1 year ago
bugherder

https://hg.mozilla.org/mozilla-central/rev/36d26905ef58

👁 Image	Mihai Boldan, Desktop QA [:mboldan]
	Updated • 1 year ago

👁 Image	Max Inden Assignee
	Comment 5 • 1 year ago

Posting the results of this patch here in order to be able to link to a public resource.

This patch improved 95th percentile and 75th percentile of http3_timer_delayed metric. The 75th percentile is now below or close to our 1 MS timer accuracy limit.

https://glam.telemetry.mozilla.org/fog/probe/http3_timer_delayed/explore?visiblePercentiles=%5B95%2C75%5D

Improved timer accuracy improves various QUIC components, e.g. RTT measurement and thus congestion control.