Aaron Jensen <aaronjensen@gmail.com> writes:

Adding Gerd Möllmann.

The flicker appears to have been introduced by the work done in 414de92a562

Initial child frames based on master (Mon Oct 21 18:32:04 2024 +0200, 5 months ago) <Gerd Möllmann>

It's a fairly large change set, so I don't know yet what might be causing it. I can reproduce it fairly consistently using my own setup, but I don't know how to narrow it down to something from Emacs -Q because it appears to be related to CPU utilization and/or rapid updating of buffers that are not currently visible.

Aaron

On Sat, Mar 15, 2025 at 9:49 AM, Aaron Jensen <aaronjensen@gmail.com> wrote:

Here's a video clip: https://share.cleanshot.com/x8zWLgYf

It seems to happen more often when there is significant load. In this case, I was running an 8 worker web server in a vterm in Emacs and a set of 8 parallel UI tests against it. The server was printing log messages at a rapid rate, but that vterm buffer was not visible.

Aaron

I'm afraid I have not the slightest idea.

414de92a562 concerns only ttys, AFAICT. I've looked through the commit again right now. The changes to NS code directly are only trivial ones
(1 -> true, 0 -> false etc.). So it would have to be something in redisplay_internal or something similar, in code not specific to NS that is used on all window systems, and I don't see a change there that could cause something with the symptoms you describe.

Adding Alan Third in CC. Maybe he has an idea.