volk: fix build for apple silicon

[hexagonal-sun]

Motivation for this change

This fixes the build of volk for apple M1 machines. Until cpu_features gains darwin support, there is no prospect of running gnuradio with Nix on apple silicon. Credit to @michaelld who's work this is based on.

Things done

• Built on platform(s)
  • x86_64-linux
  • aarch64-linux
  • x86_64-darwin
  • aarch64-darwin
• For non-Linux: Is sandbox = true set in nix.conf? (See Nix manual)
• Tested, as applicable:
  • NixOS test(s) (look inside nixos/tests)
  • and/or package tests
  • or, for functions and "core" functionality, tests in lib/tests or pkgs/test
  • made sure NixOS tests are linked to the relevant packages
• Tested compilation of all packages that depend on this change using nix-shell -p nixpkgs-review --run "nixpkgs-review rev HEAD". Note: all changes have to be committed, also see nixpkgs-review usage
• Tested basic functionality of all binary files (usually in ./result/bin/)
• 22.05 Release Notes (or backporting 21.11 Release notes)
  • (Package updates) Added a release notes entry if the change is major or breaking
  • (Module updates) Added a release notes entry if the change is significant
  • (Module addition) Added a release notes entry if adding a new NixOS module
  • (Release notes changes) Ran nixos/doc/manual/md-to-db.sh to update generated release notes
• Fits CONTRIBUTING.md.

[michaelld]

FYI Volk 2.5.1 was recently released that allows for either an external cpu_features or the internal version, updated so-as to not require this patch. I don't know what version of cpu_features is provided in NixOS, but if it's recent enough to support M1 / ARM64 then update Volk to the current release & use the external cpu_features. I have not updated Volk in MacPorts yet due to my heavy workload. I hope to get it in the next week or so.

[hexagonal-sun]

FYI Volk 2.5.1 was recently released that allows for either an external cpu_features or the internal version, updated so-as to not require this patch.

Ah nice! I think we have a PR for updating volk somewhere. I know that cpu_features upstream has been working to add M1 support, have they got enough to now build volk?

[doronbehar]

FYI Volk 2.5.1 was recently released that allows for either an external cpu_features or the internal version, updated so-as to not require this patch. I don't know what version of cpu_features is provided in NixOS, but if it's recent enough to support M1 / ARM64 then update Volk to the current release & use the external cpu_features. I have not updated Volk in MacPorts yet due to my heavy workload. I hope to get it in the next week or so.

@hexagonal-sun or @michaelld , could either of you check whether the volk from #160121 passes a build at your M1 computers? I noticed that even with volk 2.5.1 the build fails according to ofborg. If I understand correctly, you are saying that I shouldn't apply the patch? Or should we package cpu-features and only then it will be fixed? You are welcome to send a PR to my doronbehar:pkg/gnuradio/update branch.

[doronbehar]

@SuperSandro2000 it'd have been nice if you had read the comment I left, indicating that perhaps this PR could have been superseded by #160121. Plus, the ofborg build for volk on aarch64-darwin failed.

[hexagonal-sun]

@doronbehar Ah, sorry this got merged. Feel free to revert. Yes, I think we may as well target this at 2.5.1 as we'll have more options. It looks like cpu_features isn't packaged in nixpkgs, I think it makes sense to package that up and make volk use that. What are your thoughts?

[SuperSandro2000]

@SuperSandro2000 it'd have been nice if you had read the comment I left, indicating that perhaps this PR could have been superseded by #160121. Plus, the ofborg build for volk on aarch64-darwin failed.

I thought this was somehow about gnuradio, unrelated to this one.

[hexagonal-sun]

@doronbehar @michaelld I've just checked #160121 and it doesn't build on aarch64-darwin I'm afraid. I've also replaced the cpu_features submodule that volk uses with the very latests commits on the main branch. That doesn't seem to work either. It looks like cpu_features needs more fixes before this works.

[michaelld]

@hexagonal-sun well drat ... I haven't had time to look at cpu_features since they closed the "support for M1" PR ... guess I need to get there sooner rather than later, as I need to update the Volk port in MacPorts & this will require either an external cpu_features or patching the submodule version

[doronbehar]

I thought this was somehow about gnuradio, unrelated to this one.

It's OK, perhaps I should have been more clear in the PR title. Also it seems that the volk update should be halted for now, according to reports by @hexagonal-sun and @michaelld , thanks for your help.

[doronbehar]

FYI, I updated to volk 3.0.0 for non aarch64-darwin platforms only at: #219179