On Thu, Jun 22, 2023 at 03:26:30PM +0200, Cayetano Santos wrote: > > > >mer. 21 juin 2023 at 22:39, Cayetano Santos <[email protected]> wrote: > > >>mer. 21 juin 2023 at 16:36, Ludovic Courtès <[email protected]> > >>wrote: > > > >> Hey! > >> > >> The benchmark you posted, Cayetano, is: > >> > >> julia -e 'using Pkg; Pkg.add("BenchmarkTools"); using BenchmarkTools; N > >> = 1000; A = rand(N, N); B = rand(N, N); @btime $A*$B'
I've been having a hard time with that command, so I've been running
julia -e 'using Pkg; Pkg.add("BenchmarkTools"); using BenchmarkTools; N = 1000;
A = rand(N, N); B = rand(N, N); @time A*B'
I'm not sure if that's useful or not but I didn't see a different with
LIBBLAS* set.
> >>
> >> This is a matrix multiplication that gets delegated to the underlying
> >> BLAS right. Running it under ‘perf record’ confirms it:
> >>
> >> Samples: 139K of event 'cycles:u', Event count (approx.): 99624880590
> >> Overhead Command Shared Object Symbol
> >> 35.27% .julia-real libblas.so.3.9.0 [.] dgemm_
> >> 3.99% .julia-real libjulia-internal.so.1.8 [.] gc_mark_loop
> >> 2.60% .julia-real libjulia-internal.so.1.8 [.] apply_cl
> >> 1.06% .julia-real libjulia-internal.so.1.8 [.] jl_get_binding_
> >>
> >> We’re using libblas.so (presumably from the ‘lapack’ package) and not
> >> OpenBLAS, so no wonder it’s slow.
> >>
> >> Could it be that:
> >>
> >> "LIBBLAS=-lopenblas"
> >> "LIBBLASNAME=libopenblas"
> >>
> >> is ineffective? I think we have a lead!
> >
> > Are we following all instructions here ?
> >
> >
> > https://docs.julialang.org/en/v1.8/devdocs/build/distributing/#Notes-on-BLAS-and-LAPACK
> >
> > I’m thinking about the variables LIBLAPACK and LIBLAPACKNAME.
>
> To complete my previous comment, I just realised that
>
> Base.USE_BLAS64
>
> gives "true" when running fast. Guix julia gives "false".
>
> C.
I'll see what comes with switching it to blas64
--
Efraim Flashner <[email protected]> רנשלפ םירפא
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