Illegal instruction is not fixed

[kolbma]

When running sudo howdy add or sudo howdy test the only output is Illegal instruction.

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I've searched for similar issues already, and my issue has been reported, but closed without solution in current release: #101 #330

Linux distribution (if applicable): openSUSE Leap 15.2

Howdy version (sudo howdy version): Howdy 2.6.1

[kolbma]

I can't use the provided python3-dlib rpm. I've installed now the current release with pip3 install dlib.
First with pip3 install --user dlib to get a wheel.
Afterwards sudo pip3 install .cache/pip/wheels/bd/46/7c/d...ce/dlib-19.22.0-cp36-cp36m-linux_x86_64.whl and pip3 uninstall dlib.

Seems to work now. Maybe update your documentation and try to catch this error with a meaningful error message!

[boltgolt]

I'm guessing that it crashes Howdy on cv2 import, might not be a catchable error but i'll look into it

[jcdegiorgi]

Hi, I've got this same problem when sudo howdy -U myusername add Please look straight into the camera Illegal instruction

But the howdy test works perfectly though.

Ubuntu 22.04 and HP Pavilion dv3000.

Regards, Jean-Claude

[kolbma]

I've found some time to look into this...
dlib is using some CPU architecture instructionset features like SSE4 or AVX.

In precompiled binaries (on modern hardware) this defaults to enabled AVX instructions.
When running this dlib on older hardware these are illegal instructions for the CPU.

But when installing/compiling dlib on the local hardware with pip, cmake is detecting the correct available instructionset and uses right features for compiling dlib. So e.g. using SSE4 instead of AVX or disabling both and using slower generic machine instructions.

It is also possible to set this by hand: https://github.com/davisking/dlib/blob/1bebccfb8728f6112d6142ba24f2dd65970ff6a2/setup.py#L20-L22

To exclude certain options in the cmake config use --no:
    for example:
    --no USE_AVX_INSTRUCTIONS: will set -DUSE_AVX_INSTRUCTIONS=no

In dlib is also a check for the instruction sets...
https://github.com/davisking/dlib/blob/1bebccfb8728f6112d6142ba24f2dd65970ff6a2/dlib/simd/simd_check.h#L153-L171

    inline void warn_about_unavailable_but_used_cpu_instructions()
    {
#if defined(DLIB_HAVE_AVX2)
        if (!cpu_has_avx2_instructions())
            std::cerr << "Dlib was compiled to use AVX2 instructions, but these aren't available on your machine." << std::endl;
#elif defined(DLIB_HAVE_AVX)
        if (!cpu_has_avx_instructions())
            std::cerr << "Dlib was compiled to use AVX instructions, but these aren't available on your machine." << std::endl;
#elif defined(DLIB_HAVE_SSE41)
        if (!cpu_has_sse41_instructions())
            std::cerr << "Dlib was compiled to use SSE41 instructions, but these aren't available on your machine." << std::endl;
#elif defined(DLIB_HAVE_SSE3)
        if (!cpu_has_sse3_instructions())
            std::cerr << "Dlib was compiled to use SSE3 instructions, but these aren't available on your machine." << std::endl;
#elif defined(DLIB_HAVE_SSE2)
        if (!cpu_has_sse2_instructions())
            std::cerr << "Dlib was compiled to use SSE2 instructions, but these aren't available on your machine." << std::endl;
#endif
    }

This gets called by the python module here: https://github.com/davisking/dlib/blob/1bebccfb8728f6112d6142ba24f2dd65970ff6a2/tools/python/src/dlib.cpp#L42

I've opened https://github.com/davisking/dlib/issues/2675

[boltgolt]

Awesome work @kolbma! Hopefully the dlib people can look at it soon