1171441 - Add a way to determine if an AudioParam is constant for a block

Status: RESOLVED FIXED

(Core :: Web Audio, defect, P3)

Description

[Paul Adenot (:padenot)]

This is a nice optimization, since sometimes, having the param value that changes induces costly recomputations.

This is especially necessary since `AudioParam.value` now adds a timeline event.

Comment 1

[Bulk Bug Changes for mreavy's org]

Mass change P2->P3 to align with new Mozilla triage process.

Comment 2

[Karl Tomlinson (:karlt)]

An approximation of this is to have a simple value recorded on the AudioEventTimeline when there are no further events in the future and the last event in the past is not a SetTarget.
This would address the common case of events having already passed, and would be sufficient to address the case of making the value setter behave like setValueAtTime().
It is an easy case to detect because once the event is known simple, no further analysis of events is required (until another event is added).

Comment 3

[Karl Tomlinson (:karlt)]

This approach of comment 2 provides benchmark time reductions of 64 - 73% on Stereo Panning with Automation, 24 - 30% on Granular synthesis, 13 - 29% on Periodic Wave with Automation, and 6 - 20 % on Substractive synth.

A regression of 18% was reported on the "Stereo Panning" benchmark only on 32-bit WINNT. However, running the same comparison without the larger benchmarks, "Granular synthesis", "Synth", and "Substractive synth", does not show the same regression, implying that the apparent regression was a bleeding of one benchmark's work into another, perhaps a result of GC after the more complex graphs. The last benchmarks run in this order: "Granular synthesis", "Synth", "Substractive synth", "Stereo Panning", "Stereo Panning with Automation", "Periodic Wave with Automation".

Comment 4

[Karl Tomlinson (:karlt)]

Attachment: Bug 1171441 remove unused CancelAllEvents() r?padenot

Comment 5

[Karl Tomlinson (:karlt)]

Attachment: Bug 1171441 rename AudioEventTimeline::mValue to mDefaultValue r?padenot

mSetValue might be a more accurate name right now, but this will be the
default value when bug 1308435 is fixed. Its purpose will be to record the
value to return when there are no events, including when events have been
removed.

Depends on D188938

Comment 6

[Karl Tomlinson (:karlt)]

Attachment: Bug 1171441 unify handling of no next event and ignored next event r?padenot

Depends on D188939

Comment 7

[Karl Tomlinson (:karlt)]

Attachment: Bug 1171441 clarify distinction between start and end time of event r?padenot

Depends on D188940

Comment 8

[Karl Tomlinson (:karlt)]

Attachment: Bug 1171441 use double type for end time of event r?padenot

This retains some double precision from mDuration instead of truncating
mDuration.

Event start times are already rounded to ticks, so perhaps the end time could
be also, but that would require some care with end time out of range of
int64_t. These uses always have a subsequent event and so the end time would
not be out of range.

Changes in rendering are expected to be minor.

Depends on D188941

Comment 9

[Karl Tomlinson (:karlt)]

Attachment: Bug 1171441 move end time and value functions to AudioTimelineEvent r?padenot

so that they can be used outside of GetValuesAtTimeHelperInternal() in a
subsequent patch.

Depends on D188942

Comment 10

[Karl Tomlinson (:karlt)]

Attachment: Bug 1171441 use simple AudioEventTimeline value when it has a suitable single event r?padenot

Depends on D188943

Comment 11

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/f22fd10b14cc
rename AudioEventTimeline::mValue to mDefaultValue r=padenot
https://hg.mozilla.org/integration/autoland/rev/c23bf75d074e
unify handling of no next event and ignored next event r=padenot

Comment 12

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/d57a6e27f79e
clarify distinction between start and end time of event r=padenot
https://hg.mozilla.org/integration/autoland/rev/5ce53217bf3e
use double type for end time of event r=padenot

Comment 13

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/4d85ecdd90eb
move end time and value functions to AudioTimelineEvent r=padenot

Comment 14

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/e4787339734b
use simple AudioEventTimeline value when it has a suitable single event r=padenot

Comment 15

[Narcis Beleuzu [:NarcisB]]

https://hg.mozilla.org/mozilla-central/rev/f22fd10b14cc
https://hg.mozilla.org/mozilla-central/rev/c23bf75d074e
https://hg.mozilla.org/mozilla-central/rev/d57a6e27f79e
https://hg.mozilla.org/mozilla-central/rev/5ce53217bf3e

Comment 16

[Atila Butkovits]

https://hg.mozilla.org/mozilla-central/rev/4d85ecdd90eb
https://hg.mozilla.org/mozilla-central/rev/e4787339734b

Comment 17

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/7056fe8e144d
remove unused CancelAllEvents() r=padenot

Comment 18

[Narcis Beleuzu [:NarcisB]]

https://hg.mozilla.org/mozilla-central/rev/7056fe8e144d

Comment 19

[Andra Esanu (needinfo me)]

(In reply to Pulsebot from comment #14)

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/e4787339734b
use simple AudioEventTimeline value when it has a suitable single event
r=padenot

== Change summary for alert #39690 (as of Thu, 28 Sep 2023 09:21:09 GMT) ==

Improvements:

Ratio	Test	Platform	Options	Absolute values (old vs new)	Performance Profiles
8%	webaudio	macosx1015-64-shippable-qr	fission webrender	98.25 -> 89.92	Before/After
8%	webaudio	linux1804-64-shippable-qr	fission webrender	116.50 -> 106.83	Before/After
8%	webaudio	linux1804-64-shippable-qr	fission webrender	117.17 -> 107.75	Before/After
7%	webaudio	windows10-64-shippable-qr	fission webrender	91.83 -> 85.25

For up to date results, see: https://treeherder.mozilla.org/perfherder/alerts?id=39690