We don't intend to ever ship WebRender for users with old NVIDIA binary drivers, or if they are using llvmpipe. Limiting it to users also with AVX2 (somewhat modern CPUs) brings us to around 10% of the release population. Limiting to small screens as well should bring this number down further. We are already shipping Software WebRender in nightly and early beta to these users.

This patch ships Software WebRender to release to a small set (< 10%) of
Linux users whom we are unlikely to ever ship WebRender to. This
compromises of llvmpipe users with small screens and AVX2 support, and
NVIDIA binary driver users with small screens, AVX2 support and a driver
older than 460.32.3.

All of these users would be getting Software WebRender today in nightly
and early beta.

[Tracking Requested - why for this release]: We want to ship SW-WR to release to a small population of Linux users.

Comment on attachment 9206747 [details]
Bug 1696269 - Ship Software WebRender to release for some Linux users without WebRender.

Beta/Release Uplift Approval Request

• User impact if declined: These Linux users will continue using Basic in release.
• Is this code covered by automated tests?: Yes
• Has the fix been verified in Nightly?: No
• Needs manual test from QE?: No
• If yes, steps to reproduce:
• List of other uplifts needed: None
• Risk to taking this patch: Low
• Why is the change risky/not risky? (and alternatives if risky): We cannot verify in nightly or early beta, all of these users already get Software WebRender by default. We should see in late beta and release that these users continue to get SW-WR after it lands.

It is low risk because we have been shipping SW-WR to these users in nightly for months, and in previous early beta cycles. We should be able to disable it via the graphics blocklist should the rollout not go smoothly. It should represent under 10% of our Linux release population.

• String changes made/needed:

https://hg.mozilla.org/mozilla-central/rev/7f809d653cb1

There are a number of crashes in beta tied to sw-wr, which I've been treating as if they wouldn't affect release. I'm concerned about changing that now for 87.

(In reply to Julien Cristau [:jcristau] from comment #6)

There are a number of crashes in beta tied to sw-wr, which I've been treating as if they wouldn't affect release. I'm concerned about changing that now for 87.

Which crashes?

E.g. bug 1692815.
I just filed bug 1696420, but that might already be fixed by bug 1686244?

One other question I have is are we tracking memory usage for sw-wr vs basic?

Also, has this been through QA?

Nope. QA has been asked to look at 88 on Linux. 87 and 88 are pretty similar so we expect an overlap in any issues they might find.

FWIW, sw-wr has been enabled in early beta since 86 beta 3 (bug 1689186) and nightly since 85 (Nov 21) (bug 1677293) so it has some decent testing there.

Comment on attachment 9206747 [details]
Bug 1696269 - Ship Software WebRender to release for some Linux users without WebRender.

relman wasn't comfortable with this so we'll punt to 88.