JLD mmap benchmark

gistfile1.jl

using HDF5, JLD
const MATRIX_SIZE = 1000

# Write test file
x = rand(MATRIX_SIZE, MATRIX_SIZE)
jld = jldopen("test.jld", "w")
write(jld, "x", x)
close(jld)

macro s()
	esc(quote
		s = 0.0
		for i = 1:MATRIX_SIZE, j = 1:MATRIX_SIZE
			s += (x[i:i, j:j]::Array{Float64, 2})[1]
		end
	end)
end

function no_io()
	@s
	s
end

function standard()
	jld = jldopen("test.jld")
	x = read(jld, "x")
	@s
	close(jld)
	s
end

function mmapped()
	jld = jldopen("test.jld", mmaparrays=true)
	x = read(jld, "x")
	@s
	close(jld)
	s
end

function hyperslab()
	jld = jldopen("test.jld")
	x = plain(jld)["x"]
	@s
	close(x)
	close(jld)
	s
end

# Burn-in
no_io()
standard()
mmapped()
hyperslab()

# Performance
gc()
gc_disable()
@time no_io()
@time standard()
@time mmapped()
@time hyperslab()
gc_enable()

# On my system:
# elapsed time: 0.515120963 seconds (no_io)
# elapsed time: 0.595511348 seconds (standard)
# elapsed time: 0.588954757 seconds (mmapped)
# elapsed time: 23.050431843 seconds (hyperslab)