Test correct backend in examples test

examples/histogram.jl

@@ -5,31 +5,29 @@ include(joinpath(dirname(pathof(KernelAbstractions)), "../examples/utils.jl")) #
 
 # Function to use as a baseline for CPU metrics
 function create_histogram(input)
-    histogram_output = zeros(Int, maximum(input))
+    histogram_output = zeros(eltype(input), maximum(input))
     for i in input
         histogram_output[i] += 1
     end
     return histogram_output
 end
 
 # This a 1D histogram kernel where the histogramming happens on shmem
-@kernel function histogram_kernel!(histogram_output, input)
-    tid = @index(Global, Linear)
+@kernel unsafe_indices = true function histogram_kernel!(histogram_output, input)
+    gid = @index(Group, Linear)
     lid = @index(Local, Linear)
 
-    @uniform warpsize = Int(32)
-
-    @uniform gs = @groupsize()[1]
+    @uniform gs = prod(@groupsize())
+    tid = (gid - 1) * gs + lid
     @uniform N = length(histogram_output)
 
-    shared_histogram = @localmem Int (gs)
+    shared_histogram = @localmem eltype(input) (gs)
 
     # This will go through all input elements and assign them to a location in
     # shmem. Note that if there is not enough shem, we create different shmem
     # blocks to write to. For example, if shmem is of size 256, but it's
     # possible to get a value of 312, then we will have 2 separate shmem blocks,
     # one from 1->256, and another from 256->512
-    @uniform max_element = 1
     for min_element in 1:gs:N
 
         # Setting shared_histogram to 0
@@ -42,7 +40,7 @@ end
         end
 
         # Defining bin on shared memory and writing to it if possible
-        bin = input[tid]
+        bin = tid <= length(input) ? input[tid] : 0
         if bin >= min_element && bin < max_element
             bin -= min_element - 1
             @atomic shared_histogram[bin] += 1
@@ -58,10 +56,10 @@ end
 
 end
 
-function histogram!(histogram_output, input)
+function histogram!(histogram_output, input, groupsize = 256)
     backend = get_backend(histogram_output)
     # Need static block size
-    kernel! = histogram_kernel!(backend, (256,))
+    kernel! = histogram_kernel!(backend, (groupsize,))
     kernel!(histogram_output, input, ndrange = size(input))
     return
 end
@@ -74,9 +72,10 @@ function move(backend, input)
 end
 
 @testset "histogram tests" begin
-    rand_input = [rand(1:128) for i in 1:1000]
-    linear_input = [i for i in 1:1024]
-    all_two = [2 for i in 1:512]
+    # Use Int32 as some backends don't support 64-bit atomics
+    rand_input = Int32.(rand(1:128, 1000))
+    linear_input = Int32.(1:1024)
+    all_two = fill(Int32(2), 512)
 
     histogram_rand_baseline = create_histogram(rand_input)
     histogram_linear_baseline = create_histogram(linear_input)
@@ -86,14 +85,14 @@ end
     linear_input = move(backend, linear_input)
     all_two = move(backend, all_two)
 
-    rand_histogram = KernelAbstractions.zeros(backend, Int, 128)
-    linear_histogram = KernelAbstractions.zeros(backend, Int, 1024)
-    two_histogram = KernelAbstractions.zeros(backend, Int, 2)
+    rand_histogram = KernelAbstractions.zeros(backend, eltype(rand_input), Int(maximum(rand_input)))
+    linear_histogram = KernelAbstractions.zeros(backend, eltype(linear_input), Int(maximum(linear_input)))
+    two_histogram = KernelAbstractions.zeros(backend, eltype(all_two), Int(maximum(all_two)))
 
-    histogram!(rand_histogram, rand_input)
+    histogram!(rand_histogram, rand_input, 6)
     histogram!(linear_histogram, linear_input)
     histogram!(two_histogram, all_two)
-    KernelAbstractions.synchronize(CPU())
+    KernelAbstractions.synchronize(backend)
 
     @test isapprox(Array(rand_histogram), histogram_rand_baseline)
     @test isapprox(Array(linear_histogram), histogram_linear_baseline)

examples/memcopy.jl

@@ -16,8 +16,8 @@ function mycopy!(A, B)
     return
 end
 
-A = KernelAbstractions.zeros(backend, Float64, 128, 128)
-B = KernelAbstractions.ones(backend, Float64, 128, 128)
+A = KernelAbstractions.zeros(backend, f_type, 128, 128)
+B = KernelAbstractions.ones(backend, f_type, 128, 128)
 mycopy!(A, B)
 KernelAbstractions.synchronize(backend)
 @test A == B

examples/memcopy_static.jl

@@ -16,8 +16,8 @@ function mycopy_static!(A, B)
     return
 end
 
-A = KernelAbstractions.zeros(backend, Float64, 128, 128)
-B = KernelAbstractions.ones(backend, Float64, 128, 128)
+A = KernelAbstractions.zeros(backend, f_type, 128, 128)
+B = KernelAbstractions.ones(backend, f_type, 128, 128)
 mycopy_static!(A, B)
 KernelAbstractions.synchronize(backend)
 @test A == B

examples/performant_matmul.jl

@@ -4,7 +4,10 @@ using Test
 using Random
 include(joinpath(dirname(pathof(KernelAbstractions)), "../examples/utils.jl")) # Load backend
 
-const TILE_DIM = 32
+# We use a TILE_DIM of 16 as a safe value since while
+#  most backends support up to 1024 threads per group,
+#  Metal sometimes supports fewer.
+const TILE_DIM = 16
 
 @kernel function coalesced_matmul_kernel!(
         output, @Const(input1), @Const(input2), N, R, M,

examples/utils.jl

@@ -1,9 +1,13 @@
 # EXCLUDE FROM TESTING
-if Base.find_package("CUDA") !== nothing
-    using CUDA
-    using CUDA.CUDAKernels
-    const backend = CUDABackend()
-    CUDA.allowscalar(false)
-else
-    const backend = CPU()
+if !(@isdefined backend)
+    if Base.find_package("CUDA") !== nothing
+        using CUDA
+        using CUDA.CUDAKernels
+        const backend = CUDABackend()
+        CUDA.allowscalar(false)
+    else
+        const backend = CPU()
+    end
 end
+
+const f_type = KernelAbstractions.supports_float64(backend) ? Float64 : Float32

test/examples.jl

@@ -9,7 +9,7 @@ function find_sources(path::String, sources = String[])
     return sources
 end
 
-function examples_testsuite(backend_str)
+function examples_testsuite(backend, backend_str)
     @testset "examples" begin
         examples_dir = joinpath(@__DIR__, "..", "examples")
         examples = find_sources(examples_dir)
@@ -21,6 +21,7 @@ function examples_testsuite(backend_str)
         @testset "$(basename(example))" for example in examples
             @eval module $(gensym())
             backend_str = $backend_str
+            const backend = ($backend)()
             include($example)
             end
             @test true

test/testsuite.jl

@@ -84,7 +84,7 @@ function testsuite(backend, backend_str, backend_mod, AT, DAT; skip_tests = Set{
     end
 
     @conditional_testset "Examples" skip_tests begin
-        examples_testsuite(backend_str)
+        examples_testsuite(backend, backend_str)
     end
 
     return