host: Add AVX2 support for uhd::convert

[anilgurses]

Pull Request Details

Description

AVX2 support is implemented for uhd::convert. It was previously limited with sse2. It provides performance improvements for data type conversion.

Related Issue

N/A

Which devices/areas does this affect?

Affects the uhd::convert data conversion performance.

Testing Done

Testing is done using the tests written previously by UHD developers. It passes all previous tests and there is no need for new tests.

Checklist

• I have read the CONTRIBUTING document.
• My code follows the code style of this project. See CODING.md.
• I have updated the documentation accordingly.
• I have added tests to cover my changes, and all previous tests pass.
• I have checked all compat numbers if they need updating (FPGA compat,
  MPM compat, noc_shell, specific RFNoC block, ...)

[github-actions]

CLA Assistant Lite bot All contributors have signed the CLA ✍️ ✅

[anilgurses]

I have read the CLA Document and I hereby sign the CLA

[anilgurses]

Hi! Is there anything else needed for this PR?

[mbr0wn]

Hey @anilgurses, sorry for never responding here. The problem is that AVX2 support is not ubiquitous, and we need a way to only deploy it on demand. Something like a glibc conditional dispatch.

I was also thinking of merging this, but leaving it disabled unless explicitly enabled at compile time (this would not, for example, be the case for .deb files we distribute). But that's also work.

[mbr0wn]

All of this assumes the compiling machine has the same arch as the executing machine.

[mbr0wn]

This means AVX512 is supported by the compiler, not that it's also supported by the CPU.

[anilgurses]

Thanks for the feedback! You are right. Let me check if I can find time to implement on-demand AVX512. I'll update this PR once it's ready.