1680063 - Performance on gen6 win7 is bad

Status: RESOLVED FIXED

(Core :: Graphics: WebRender, defect)

Description

[Jeff Muizelaar [:jrmuizel]]

We seem to be spending a lot of time waiting.

Comment 1

[Jeff Muizelaar [:jrmuizel]]

Notice the big chunks of time spent in mozilla::wr::RendererOGL::WaitForGPU: https://share.firefox.dev/33vONis

Comment 2

[Jeff Muizelaar [:jrmuizel]]

Other applications seem slowed down by the WebRender running Firefox so it could be that the GPU is actually swamped.

Comment 3

[Jeff Muizelaar [:jrmuizel]]

I see the problem on 78 (with WebRender forced on) as well, so it's not a recent thing.

Comment 4

[Jeff Muizelaar [:jrmuizel]]

The same hardware seems to run just fine on Win10 even with the DirectComposition turned off.

Comment 5

[Jeff Muizelaar [:jrmuizel]]

Also seems ok on Win8.1

Comment 6

[Jeff Muizelaar [:jrmuizel]]

The Win8.1 driver is 9.17.10.4229

Comment 7

[Jeff Muizelaar [:jrmuizel]]

Looking at the gpuview traces I see high DWM times. The problem happens in all of the webrender configurations and none of the non-webrender configurations. Turning the DWM off improves things.

With WebRender off I get "Widget glass margins: left:2 top:84 right:2 bottom:2" with WebRender on I get "Widget glass margins: left:0 top:0 right:0 bottom:0"

I suspect the DWM thinks the entire window is glass.

Comment 8

[Jeff Muizelaar [:jrmuizel]]

Matt points out: This clearly doesn't run under WR - https://searchfox.org/mozilla-central/source/layout/painting/FrameLayerBuilder.cpp#4358

Comment 9

[Sotaro Ikeda [:sotaro]]

Attachment: Bug 1680063 - Add AddWindowOpaqueRegion() handling

Comment 10

[Sotaro Ikeda [:sotaro]]

D98434 is temporal implementation that is borrowed from ContainerState::ComputeOpaqueRect(). It does not handle clip correctly.

I tested it on Win7 PC with about:networking#logging and Widget:5. Glass margin became same between WebRender and CompositorD3D11.

I do not know well about FrameLayerBuilder and display items. :mattwoodrow knows about them and could provide correct implementation.

Comment 11

[Jeff Muizelaar [:jrmuizel]]

This patch makes an enormous difference for me.

Comment 12

[Jeff Muizelaar [:jrmuizel]]

e.g. DWM gpu times go from 23.5ms down to 6.5ms

Comment 13

[Markus Stange [:mstange]]

I'll be taking a look at this in bug 1680291.

Comment 14

[Matt Woodrow (:mattwoodrow)]

Attachment: Bug 1680063 - Record opaque background color items as part of the DL builders opaque region when using WebRender. r?mstange,miko

Comment 15

[Matt Woodrow (:mattwoodrow)]

The attached patch (very similar to Sotaro's one) just identifies the exact display items that are present on win7 and forwards their opaque area to the DL builder.

I think we should take this in the meantime, and uplift it to beta to fix the current win7 performance problems.

We should still work on bug 1680291 for future releases, but I believe the short term fix will be a much lower risk for uplift.

Comment 16

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/ed20bde0b75f
Record opaque background color items as part of the DL builders opaque region when using WebRender. r=mstange

Comment 17

[Matt Woodrow (:mattwoodrow)]

Comment on attachment 9190916 [details]
Bug 1680063 - Record opaque background color items as part of the DL builders opaque region when using WebRender. r?mstange,miko

Beta/Release Uplift Approval Request

• User impact if declined: Significantly reduced performance on Windows 7 (with Aero Glass). We are currently disabling WebRender on gen6 intel hardware due to this issue (bug 168016), but the performance drop will affect higher power cards too.

If we land this, we can remove the gen6 block instead, and ship WebRender to a lot more users.

• Is this code covered by automated tests?: No
• Has the fix been verified in Nightly?: No
• Needs manual test from QE?: No
• If yes, steps to reproduce: Manual testing already completed using try builds
• List of other uplifts needed: None
• Risk to taking this patch: Low
• Why is the change risky/not risky? (and alternatives if risky): This just adds an opaque region, which tells the Windows DWM compositor that it doesn't need to do the Glass effects on that subset of the window.

The fix is very targeted for the specific display items that we have on Windows 7. The failure case if these change is that we go back to drawing too much glass.

• String changes made/needed:

Comment 18

[Dorel Luca [:dluca]]

https://hg.mozilla.org/mozilla-central/rev/ed20bde0b75f

Comment 19

[Ryan VanderMeulen [:RyanVM]]

Comment on attachment 9190916 [details]
Bug 1680063 - Record opaque background color items as part of the DL builders opaque region when using WebRender. r?mstange,miko

Approved for 84.0b8.

Comment 20

[Ryan VanderMeulen [:RyanVM]]

https://hg.mozilla.org/releases/mozilla-beta/rev/c7c6e9a99020