wren/test/benchmark/map_numeric.lua

local start = os.clock()

local map = {}

for i = 1, 2000000 do
  map[i] = i
end

local sum = 0
for i = 1, 2000000 do
  sum = sum + map[i]
end
io.write(string.format("%d\n", sum))

for i = 1, 2000000 do
  map[i] = nil
end

io.write(string.format("elapsed: %.8f\n", os.clock() - start))
Adding map benchmark scripts. 2015-02-09 11:51:09 +01:00			`local start = os.clock()`

			`local map = {}`

Fix horrendously bad bit hashing function. hashBits() is used to generate a hash code from the same 64 bits used to represent a Wren number as a double. When building a map containing a large number of integer keys, it's important for this to do a good job scattering the bits across the 32-bit key space. Alas, it does not. Worse, the benchmark to test this happens to stop just before the performance falls off a cliff, so this was easy to overlook. This replaces it with the hash function V8 uses, which has much better performance across the numeric range. 2019-07-27 13:34:07 -07:00			`for i = 1, 2000000 do`
Adding map benchmark scripts. 2015-02-09 11:51:09 +01:00			`map[i] = i`
			`end`

			`local sum = 0`
Fix horrendously bad bit hashing function. hashBits() is used to generate a hash code from the same 64 bits used to represent a Wren number as a double. When building a map containing a large number of integer keys, it's important for this to do a good job scattering the bits across the 32-bit key space. Alas, it does not. Worse, the benchmark to test this happens to stop just before the performance falls off a cliff, so this was easy to overlook. This replaces it with the hash function V8 uses, which has much better performance across the numeric range. 2019-07-27 13:34:07 -07:00			`for i = 1, 2000000 do`
Adding map benchmark scripts. 2015-02-09 11:51:09 +01:00			`sum = sum + map[i]`
			`end`
			`io.write(string.format("%d\n", sum))`

Fix horrendously bad bit hashing function. hashBits() is used to generate a hash code from the same 64 bits used to represent a Wren number as a double. When building a map containing a large number of integer keys, it's important for this to do a good job scattering the bits across the 32-bit key space. Alas, it does not. Worse, the benchmark to test this happens to stop just before the performance falls off a cliff, so this was easy to overlook. This replaces it with the hash function V8 uses, which has much better performance across the numeric range. 2019-07-27 13:34:07 -07:00			`for i = 1, 2000000 do`
Adding map benchmark scripts. 2015-02-09 11:51:09 +01:00			`map[i] = nil`
			`end`

			`io.write(string.format("elapsed: %.8f\n", os.clock() - start))`