Supported instruction sets

[danieldk]

@rmcgibbo

I believe that this is could have been caused by the build happening to run on an older x86 machine without some instruction sets (AVX?), and it’s possible that the package doesn’t compile properly on such a machine.

Yes, this is the reason and it’s even worse, some of the builders do not even support SSE 4.1.There are two common workarounds. (1) As @nixinator says, this can usually be worked around by disabling tests, so that the compiled code does not get executed (though disabling tests is of course not nice). See e.g.:

oneDNN: disable tests to avoid illegal instructions

(2) The software may build with -march or other flags, that need to be disabled.

@rmcgibbo

What’s the minimum set of x86_64 ISA extensions supported by the hydra fleet?

I think the oldest CPU in the Hydra build farm is an Opeteron 6100 series, which supports SSE3:

List of AMD Opteron processors

@rmcgibbo

Is it a bug if a package only builds or works on a machine with some minimal set of ISA extensions that is apparently not shared by the entire hydra fleet?

I’d consider this an upstream bug, software should use CPUID and select code paths or kernels based on that. But there is a lot of machine learning software out there that doesn’t do this and simply relies on -march=native plus autovectorization.