Hi,

On Thu, 22 Jun 2023 at 15:26, Cayetano Santos via Bug reports for GNU Guix <bug-guix@gnu.org> wrote:
>> Are we following all instructions here ?
>>
>>   https://docs.julialang.org/en/v1.8/devdocs/build/distributing/#Notes-on-BLAS-and-LAPACK

[...]

>   Base.USE_BLAS64
>
> gives "true" when running fast. Guix julia gives "false".

When I try USE_BLAS64=1, then I get:

--8<---------------cut here---------------start------------->8---
┌ Error: No loaded BLAS libraries were built with ILP64 support
└ @ LinearAlgebra.BLAS /tmp/guix-build-julia-1.8.3.drv-0/julia-1.8.3/usr/share/julia/stdlib/v1.8/LinearAlgebra/src/blas.jl:155
Quitting.
--8<---------------cut here---------------end--------------->8---

And from the documentation above, it reads:

        [...] while on 64-bit architectures, Julia builds OpenBLAS to
        use 64-bit integers (ILP64). It is essential that all Julia
        functions that call BLAS and LAPACK API routines use integers of
        the correct width.

Well using the patch attached, I get:

    6.884 ms (2 allocations: 7.63 MiB)

compared to the previous

    494.345 ms (2 allocations: 7.63 MiB)

WDYT about this patch?