Hardware support

I'm trying to quantify what percentage of Firefox users could actually use this proposal.

Using [1] and [2], here's what I got. Note: this is desktop only data.

For desktop we have ~97% x86/x86_64 usage between Intel/AMD. The remaining ~3% looks like apple silicon if I'm reading right for our only major AArch64 usage.

ARMv8-A NEON fp16 3% implied from Apple Silicon

F16C: No direct data. For Intel it was added in Ivy Bridge. The successor, Haswell, introduced AVX2. We have 82% support for AVX and 72% for AVX2, so I would guess F16C is somewhere between there?

AVX-512 fp16: Only in Xeon, so I'm assuming no usage.

@SPY (or anyone else) do you have any more accurate usage numbers here?

I'm going to see if I can find any mobile usage numbers, but that will take a longer time as our pre-generated dashboards don't see to track this.

[1] https://data.firefox.com/dashboard/hardware
[2] https://firefoxgraphics.github.io/telemetry/#view=system

Start with the Firefox hardware dashboard and the Firefox Graphics telemetry view linked as [1] and [2]. Check whether mobile usage data is available, then establish accurate support percentages for ARMv8-A NEON fp16, F16C, and AVX-512 fp16; the issue is done when those figures are reported clearly.