increase stability

[ChristopherHX]

• use snmalloc instead of system allocator
• synchronize x11 access

[trathborne]

Thanks! This makes Minecraft 100% stable on my quad-core haswell xeon + quadro p2200 5G with nvidia driver 510. On my dual-core haswell + geforce 730M 2G and nvidia driver 470, I still get xcb thread syncronization errors. I'm not sure if it's the different driver, the less powerful host, or the less video ram, or some combination thereof.

If there's some sort of trace that would help track this down, please let me know.

[ChristopherHX]

I don't know how to debug this xcb thread synchronization errors.

I actually just added a mutex lock for every eglut / glfw api call, which may call x11 code.
I could have missed one or your xcb version is buggy.

I read that old xcb versions ignored that kind of threading issue so it is unlikely to happen on ubuntu 22.04.
Some semi current xcb/x11 client libraries seem to be more affected than the latest xcb/x11 client.

The x11 issues has been for me a very rare phenomenon even before I added the mutex synchronization

[trathborne]

Thanks for the details. My two systems are both up-to-date Ubuntu Jammy 22.04.1 so it can't be an xcb version difference. My guess is that the older nvidia driver and/or slower machine makes the problem more frequent.

I will try:

• shifting the xcb version around as far as I can under Ubuntu 22.04.1
• looking at your changes and trying to trace which eglut/glfw call triggers the problem
• upgrading to Ubuntu 22.10

[trathborne]

I examined your changes ... so you take the lock before every eglut/glfw call, and taking the lock is idempotent so any other thread which uses these functions will block forever. Since I'm still getting that xcb error, there must be another thread that does not use that lock making the call. I can only conclude that it's in code for which we don't have the source, so even if we can find where it is, we probably can't fix it. ☹️

I'm holding off on my Ubuntu upgrade but I'll let you know if that helps.

In the meantime ... Minecraft Java works great 😉

[ChristopherHX]

I can only conclude that it's in code for which we don't have the source, so even if we can find where it is, we probably can't fix it.

You can use wayland, the game doesn't use xcb, or it is memory corruption that happens randomly.

Configure the launcher to use glfw, tell glfw to use wayland and all xcb error are compiled away.