[WIP] Option to use system MKL instead of MKL_jll

Project.toml

@@ -8,6 +8,8 @@ Libdl = "8f399da3-3557-5675-b5ff-fb832c97cbdb"
 LinearAlgebra = "37e2e46d-f89d-539d-b4ee-838fcccc9c8e"
 MKL_jll = "856f044c-d86e-5d09-b602-aeab76dc8ba7"
 PackageCompiler = "9b87118b-4619-50d2-8e1e-99f35a4d4d9d"
+Pkg = "44cfe95a-1eb2-52ea-b672-e2afdf69b78f"
+Preferences = "21216c6a-2e73-6563-6e65-726566657250"
 
 [compat]
 MKL_jll = "2021"

deps/build.jl

@@ -1,15 +1,63 @@
-using MKL
+# using MKL
+using Preferences
+using Pkg
+using Libdl
 
-if VERSION > MKL.JULIA_VER_NEEDED
-    exit() # Don't want to build the system image, since we will use LBT
+const JULIA_VER_NEEDED = v"1.7.0-DEV.641"
+is_lbt_available() = VERSION > JULIA_VER_NEEDED
+
+function find_uuid_in_project(name)
+    get(Pkg.Types.EnvCache().project.deps, name, nothing)
 end
 
-using PackageCompiler
-using MKL_jll
+if is_lbt_available()
+    # Julia version >= 1.7: Use LBT
+    const MKL_uuid = find_uuid_in_project("MKL")
+
+    # 1. update preferences based on env variables if necessary
+    if haskey(ENV, "JULIA_MKL_USE_JLL")
+        use_jll = lowercase(get(ENV, "JULIA_MKL_USE_JLL", "true"))
+        set_preferences!(MKL_uuid, "use_jll" => use_jll)
+    end
+
+    if haskey(ENV, "JULIA_MKL_PATH")
+        mkl_path = lowercase(get(ENV, "JULIA_MKL_PATH", "true"))
+        set_preferences!(MKL_uuid, "mkl_path" => mkl_path)
+    end
+
+    @show has_preference(MKL_uuid, "use_jll")
+
+    # 2. set up libraries
+    use_jll = load_preference(MKL_uuid, "use_jll", "true")
+    mkl_path = load_preference(MKL_uuid, "mkl_path", "")
 
-# if no environment variable ENV["USE_BLAS64"] is set install.jl
-# tries to change USE_BLAS64 = false
-const USEBLAS64 = parse(Bool,get(ENV, "USE_BLAS64","false"))
+    if parse(Bool, use_jll)
+        @info "MKL provider: MKL_jll (default)."
+        using MKL_jll # force download of artifacts
+    else
+        @info "MKL provider: System"
+        mkl_path != "" && (@info "Explicit MKL path set: ")
+
+        @info "Checking availability of libmkl_core and libmkl_rt"
+        if find_library(["libmkl_core"], mkl_path) == ""
+            error("libmkl_core could not be found")
+        end
+        if find_library(["libmkl_rt"], mkl_path) == ""
+            error("libmkl_rt could not be found")
+        end
+    end
+else
+    # Julia versions < 1.7: Build a custom system image
+    using PackageCompiler
+    using MKL_jll
+
+    # if no environment variable ENV["USE_BLAS64"] is set install.jl
+    # tries to change USE_BLAS64 = false
+    const USEBLAS64 = parse(Bool,get(ENV, "USE_BLAS64","false"))
+
+    include("../src/install.jl")
+    enable_mkl_startup()
+end
 
-include("../src/install.jl")
-enable_mkl_startup()
+# Why?
+using MKL

src/MKL.jl

@@ -1,9 +1,38 @@
 module MKL
 
-using MKL_jll
+using Preferences
 
-JULIA_VER_NEEDED = v"1.7.0-DEV.641"
-VERSION > JULIA_VER_NEEDED && using LinearAlgebra
+const JULIA_VER_NEEDED = v"1.7.0-DEV.641"
+is_lbt_available() = VERSION > JULIA_VER_NEEDED
+
+const use_jll = parse(Bool, @load_preference("use_jll", "true"))
+
+const MKL_uuid = Base.PkgId(MKL).uuid
+@show use_jll
+@show has_preference(MKL_uuid, "use_jll")
+@show load_preference(MKL_uuid, "use_jll")
+
+if use_jll
+    # MKL_jll
+    using MKL_jll
+    MKL_jll.is_available() || error("MKL.jl not properly configured, please run `Pkg.build(\"MKL\")`.")
+else
+    # System MKL
+    using Libdl
+    mkl_path = @load_preference("mkl_path", "")
+    @show mkl_path
+    const libmkl_core = find_library(["libmkl_core"], mkl_path == "" ? [""] : [mkl_path])
+    @show libmkl_core
+    const libmkl_rt = find_library(["libmkl_rt"], mkl_path == "" ? [""] : [mkl_path])
+    @show libmkl_rt
+    @show x = dlopen(libmkl_rt)
+    @show dlclose(x)
+    if libmkl_core == "" || libmkl_rt == ""
+        error("MKL.jl not properly configured, please run `Pkg.build(\"MKL\")`.")
+    end
+end
+
+is_lbt_available() && using LinearAlgebra
 
 if Base.USE_BLAS64
     const MKLBlasInt = Int64
@@ -38,11 +67,11 @@ function set_interface_layer(interface = Base.USE_BLAS64 ? INTERFACE_ILP64 : INT
 end
 
 function __init__()
-    if MKL_jll.is_available()
-        set_threading_layer()
-        set_interface_layer()
-        VERSION > JULIA_VER_NEEDED && BLAS.lbt_forward(libmkl_rt, clear=true)
-    end
+    # if MKL_jll.is_available()
+    # set_threading_layer()
+    # set_interface_layer()
+    # is_lbt_available() && BLAS.lbt_forward(libmkl_rt, clear=true)
+    # end
 end
 
 function mklnorm(x::Vector{Float64})
@@ -51,6 +80,7 @@ function mklnorm(x::Vector{Float64})
           length(x), x, 1)
 end
 
-VERSION > JULIA_VER_NEEDED && include("install.jl")
+# Carsten: Unnecessary?!
+is_lbt_available() && include("install.jl")
 
 end # module