1642629 - Various frame building optimizations

Status: RESOLVED FIXED

(Core :: Graphics: WebRender, enhancement, P3)

Comment 1

[Nicolas Silva [:nical]]

Attachment: Bug 1642629 - Reduce the amount of vector reallocation when adding primitives to batches. r=gw

Comment 2

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/055e358cab6c
Reduce the amount of vector reallocation when adding primitives to batches. r=gw

Comment 3

[Nicolas Silva [:nical]]

Attachment: Bug 1642629 - preallocate a few vectors in CompositeState. r=gw

These vectors are rebuilt once per frame. we can't recycle them because they are sent to the renderer. On a 4k screen for most sites the element counts are low enough that we can get away with preallocation from a pessimistic estimate, but high enough that reallocation happens a few times per frame and takes a small but visible portion of the profile.

Comment 4

[Nicolas Silva [:nical]]

Attachment: Bug 1642629 - Only track per-item rects in batches if a per-batch approximation isn't good enough. r=gw

Tested this on a few pages and it lets us avoid allocating per-item rects for roughly a quarter to a third of the batches. For batches that end up allocating per item rects we get to allocate fewer of them. It also further reduces the amount of times we need to test all item rects against intersections.

Comment 5

[Nicolas Silva [:nical]]

Attachment: Bug 1642629 - Avoid iterating over all batch item rects in some cases. r=gw

Comment 6

[Narcis Beleuzu [:NarcisB]]

https://hg.mozilla.org/mozilla-central/rev/055e358cab6c

Comment 7

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/3d4463013cc1
preallocate a few vectors in CompositeState. r=gw
https://hg.mozilla.org/integration/autoland/rev/d90ad820b1f0
Avoid iterating over all batch item rects in some cases. r=kvark

Comment 8

[Bogdan Tara[:bogdan_tara | bogdant]]

https://hg.mozilla.org/mozilla-central/rev/3d4463013cc1
https://hg.mozilla.org/mozilla-central/rev/d90ad820b1f0

Comment 9

[Nicolas Silva [:nical]]

Attachment: Bug 1642629 - Remove the lookback limit for alpha batches. r=kvark

An alternative patch to take only if we don't land https://phabricator.services.mozilla.com/D79545

The main observations here are:

• In the vast majority of times we find a compatible bacth or intersect an incompatible one within 3 iterations when looking for batch candidates.
• In addition, most of the time we don't need to iterate per-item rects thanks to a fast path kleveraging per-batch bounding rects, making it reasonably cheap to iterate over more batches.

This gives us room to allow ourselves to visit a lot more batches without a large impact on CPU time (under the assumption that removing a handful of draw calls will more than make up for the extra iterations).

Depends on D79479

Comment 10

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/853d601fe2e1
Only track per-item rects in batches if a per-batch approximation isn't good enough. r=kvark

Comment 11

[Nicolas Silva [:nical]]

Attachment: Bug 1642629 - Recycle the surface info vector in frame building. r=gw

This vector is usually small, but on some pages it can be fairly large (500+ in https://forum.xda-developers.com/redmi-note-3/development for example).

Comment 12

[Nicolas Silva [:nical]]

Attachment: Bug 1642629 - Recycle a couple of vectors in PictureUpdateState. r=gw

Depends on D79855

Comment 13

[Nicolas Silva [:nical]]

Attachment: Bug 1642629 - Recycle dirty_region_stack in FrameBuilder. r=gw

Depends on D79857

Comment 14

[Narcis Beleuzu [:NarcisB]]

https://hg.mozilla.org/mozilla-central/rev/853d601fe2e1

Comment 15

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/149ca53d3549
Remove the lookback limit for alpha batches. r=kvark

Comment 16

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/217914372d03
Recycle the surface info vector in frame building. r=gw

Comment 17

[Razvan Maries]

Backed out for WebRender bustages.

Push with failure: https://treeherder.mozilla.org/#/jobs?repo=autoland&group_state=expanded&resultStatus=pending%2Crunning%2Csuccess%2Ctestfailed%2Cbusted%2Cexception&searchStr=webrender&revision=217914372d03fefa9da57b87d646dff54df351ea

Failure log: https://treeherder.mozilla.org/logviewer.html#?job_id=306558646&repo=autoland

Backout: https://hg.mozilla.org/integration/autoland/rev/a184a8ccba8b70900a24b3189570ee167ba957b3

Comment 18

[Razvan Maries]

https://hg.mozilla.org/mozilla-central/rev/149ca53d3549

Comment 19

[Nicolas Silva [:nical]]

Attachment: Bug 1642629 - Regroup recycled data structures into scratch buffers. r=gw

This change just restructures the recycling added in previouscommits.

Comment 20

[Nicolas Silva [:nical]]

Attachment: Bug 1642629 - Recycle shared clips allocation in picture.rs. r=kvark

Depends on D80096

Comment 21

[Nicolas Silva [:nical]]

Attachment: Bug 1642629 - Reserve items in SegmentBuilder before simple loops. r=kvark

Depends on D80178

Comment 22

[Nicolas Silva [:nical]]

Attachment: Bug 1642629 - Recycle FrameVisibilityState's clip_chain_stack and surface_stack. r=kvark

Depends on D80192

Comment 23

[Nicolas Silva [:nical]]

Attachment: Bug 1642629 - Preallocate the primitive headers vector. r=kvark

This patch a simple utility to help with pre-allocating vectors that we can't recycle and use it with the primitive headers.

Depends on D80193

Comment 24

[Nicolas Silva [:nical]]

Attachment: Bug 1642629 - Preallocate CompositeStateDescriptor vectors. r=kvark

Vector reallocations in CompositeState::push_surface are taking about 2% of total frame building time before this patch. There was an effort at preallocating some with constant values but I suspect these constants haven't been updated along with picture cachign heuristics.

Depends on D80194

Comment 25

[Nicolas Silva [:nical]]

Attachment: Bug 1642629 - Reserve GpuBlockData vector before pushing in a loop. r=kvark

Comment 26

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/33d6d6b9097d
Recycle the surface info vector in frame building. r=gw
https://hg.mozilla.org/integration/autoland/rev/683b75cdd3c4
Recycle a couple of vectors in PictureUpdateState. r=gw
https://hg.mozilla.org/integration/autoland/rev/88dd02d36e0d
Recycle dirty_region_stack in FrameBuilder. r=gw
https://hg.mozilla.org/integration/autoland/rev/073fe13cd98b
Regroup recycled data structures into scratch buffers. r=gw
https://hg.mozilla.org/integration/autoland/rev/a076f17ed2da
Recycle shared clips allocation in picture.rs. r=kvark
https://hg.mozilla.org/integration/autoland/rev/2195069a75c9
Reserve items in SegmentBuilder before simple loops. r=kvark
https://hg.mozilla.org/integration/autoland/rev/325a298e5e11
Recycle FrameVisibilityState's clip_chain_stack and surface_stack. r=kvark

Comment 27

[Nicolas Silva [:nical]]

Attachment: Bug 1642629 - Preallocate gpu cache texture vectors. r=gw

Comment 28

[Nicolas Silva [:nical]]

Attachment: Bug 1642629 - Reserve sorted polygon list before pushing know number of split planes into it. r=gw

Depends on D80437

Comment 29

[Noemi Erli[:noemi_erli]]

Backed out 7 changesets (Bug 1642629) for causing multiple failures and crashes CLOSED TREE

Push with failures: https://treeherder.mozilla.org/#/jobs?repo=autoland&group_state=expanded&selectedTaskRun=OpzTYVBCS5Ka0LekOgmZew.0&resultStatus=pending%2Crunning%2Csuccess%2Ctestfailed%2Cbusted%2Cexception&searchStr=windows%2C10%2Cx64%2Cwebrender%2Cdebug%2Cmochitests%2Ctest-windows10-64-qr%2Fdebug-mochitest-browser-chrome-e10s-5%2Cm%28bc5%29&revision=325a298e5e119ecb71223516e6c9b538c6057c9c

Failure log: https://treeherder.mozilla.org/logviewer.html#?job_id=307049171&repo=autoland
https://treeherder.mozilla.org/logviewer.html#/jobs?job_id=307038692&repo=autoland&lineNumber=110373

Backout: https://hg.mozilla.org/integration/autoland/rev/fa015682f65310416d2a40a146a7e8d004dd81d7

Comment 30

[Nicolas Silva [:nical]]

Attachment: Bug 1642629 - Preallocate the batches and batch rects vectors. r=gw

It would be wasteful to preallocate all batch builders because the majority of them have only a single batch, while typically only one will will have many batches. Thankfully we can acurately guess which pictures will produce many batches by checking whether they have more than one cluster.

Comment 31

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/93505e39bf57
Recycle the surface info vector in frame building. r=gw
https://hg.mozilla.org/integration/autoland/rev/9c4d5596e220
Recycle a couple of vectors in PictureUpdateState. r=gw
https://hg.mozilla.org/integration/autoland/rev/6203b2994812
Recycle dirty_region_stack in FrameBuilder. r=gw
https://hg.mozilla.org/integration/autoland/rev/dc3d4d706d11
Regroup recycled data structures into scratch buffers. r=gw
https://hg.mozilla.org/integration/autoland/rev/d7ddc0cdffa2
Recycle shared clips allocation in picture.rs. r=kvark
https://hg.mozilla.org/integration/autoland/rev/7cbc9b5f00f1
Reserve items in SegmentBuilder before simple loops. r=kvark
https://hg.mozilla.org/integration/autoland/rev/f26158a3994c
Recycle FrameVisibilityState's clip_chain_stack and surface_stack. r=kvark
https://hg.mozilla.org/integration/autoland/rev/ac1dec27b771
Preallocate the primitive headers vector. r=kvark
https://hg.mozilla.org/integration/autoland/rev/1e531a6c2590
Preallocate CompositeStateDescriptor vectors. r=kvark
https://hg.mozilla.org/integration/autoland/rev/a16036b4b36c
Reserve GpuBlockData vector before pushing in a loop. r=kvark
https://hg.mozilla.org/integration/autoland/rev/17684b39b0ba
Preallocate gpu cache texture vectors. r=gw
https://hg.mozilla.org/integration/autoland/rev/e891a846e7f3
Reserve sorted polygon list before pushing know number of split planes into it. r=gw
https://hg.mozilla.org/integration/autoland/rev/45ef8e463b6e
Preallocate the batches and batch rects vectors. r=gw

Comment 32

[Razvan Maries]

https://hg.mozilla.org/mozilla-central/rev/93505e39bf57
https://hg.mozilla.org/mozilla-central/rev/9c4d5596e220
https://hg.mozilla.org/mozilla-central/rev/6203b2994812
https://hg.mozilla.org/mozilla-central/rev/dc3d4d706d11
https://hg.mozilla.org/mozilla-central/rev/d7ddc0cdffa2
https://hg.mozilla.org/mozilla-central/rev/7cbc9b5f00f1
https://hg.mozilla.org/mozilla-central/rev/f26158a3994c
https://hg.mozilla.org/mozilla-central/rev/ac1dec27b771
https://hg.mozilla.org/mozilla-central/rev/1e531a6c2590
https://hg.mozilla.org/mozilla-central/rev/a16036b4b36c
https://hg.mozilla.org/mozilla-central/rev/17684b39b0ba
https://hg.mozilla.org/mozilla-central/rev/e891a846e7f3
https://hg.mozilla.org/mozilla-central/rev/45ef8e463b6e