WR is sluggish on google docs

[kvark]

Platform: Linux/Intel iGPU
Firefox WR is nearly unusable on editing/scrolling a long google document.
Gecko profile shows:

• the backend is 88% waiting for work
• the renderer spends 50% doing work, bigger half of which is spent in "__driDriverGetExtensions_i915". This is neither expected or fortunate, and we need to find a way to trigger less extension checks in Mesa drivers.

[staktrace]

FYI, you need to hit the 'share' button on the profile in order to get a URL that can be shared. The URL you have is a "local" profile URL and so not really useful.

[kvark]

Thanks @staktrace , fixed now.
Looking at Mesa sources now, they are somewhat different from the stack:

PUBLIC const __DRIextension **__driDriverGetExtensions_i915(void)
{
   globalDriverAPI = &i915_driver_api;

   return i915_driver_extensions;
}

[gw3583]

@kvark @jrmuizel This is probably no longer relevant and/or tracked by specific bugs in bugzilla?