Re: Lua/LuaJIT2 performance on Android

[Mike Pall <mikelu-1104@...>]

Josh Haberman wrote:
> Mike Pall <mikelu-1104 <at> mike.de> writes:
> > Oh, well. Floating-point benchmarks are not a good way to compare
> > soft-float VMs. Maybe try again with fannkuch or nsieve.
> 
> Where is the right place to obtain these?  The official
> shootout website does not seem to list nsieve anymore, and
> has "fannkuch-redux" but not "fannkuch" (are they the same
> thing?)

The two fannkuchs just have a different output. The benchmarks are
rather short, so I'm attaching them here for future archival. You
get nsieve-bit as a bonus. Run them with a scaling factor of 7 for
nsieve and 9 for fannkuch to get reasonable execution times on ARM.

--Mike

-- Lua benchmark: fannkuch-redux. Written by Mike Pall. Public domain.

local function fannkuch(n)
  local p, q, s, sign, maxflips, sum = {}, {}, {}, 1, 0, 0
  for i=1,n do p[i] = i; q[i] = i; s[i] = i end
  repeat
    -- Copy and flip.
    local q1 = p[1]				-- Cache 1st element.
    if q1 ~= 1 then
      for i=2,n do q[i] = p[i] end		-- Work on a copy.
      local flips = 1
      repeat
	local qq = q[q1]
	if qq == 1 then				-- ... until 1st element is 1.
	  sum = sum + sign*flips
	  if flips > maxflips then maxflips = flips end -- New maximum?
	  break
	end
	q[q1] = q1
	if q1 >= 4 then
	  local i, j = 2, q1 - 1
	  repeat q[i], q[j] = q[j], q[i]; i = i + 1; j = j - 1; until i >= j
	end
	q1 = qq; flips = flips + 1
      until false
    end
    -- Permute.
    if sign == 1 then
      p[2], p[1] = p[1], p[2]; sign = -1	-- Rotate 1<-2.
    else
      p[2], p[3] = p[3], p[2]; sign = 1		-- Rotate 1<-2 and 1<-2<-3.
      for i=3,n do
	local sx = s[i]
	if sx ~= 1 then s[i] = sx-1; break end
	if i == n then return sum, maxflips end	-- Out of permutations.
	s[i] = i
	-- Rotate 1<-...<-i+1.
	local t = p[1]; for j=1,i do p[j] = p[j+1] end; p[i+1] = t
      end
    end
  until false
end

local n = tonumber(arg and arg[1]) or 3
local sum, flips = fannkuch(n)
io.write(sum, "\nPfannkuchen(", n, ") = ", flips, "\n")

-- Lua benchmark: nsieve. Written by Mike Pall. Public domain.

local function nsieve(p, m)
  for i=2,m do p[i] = true end
  local count = 0
  for i=2,m do
    if p[i] then
      for k=i+i,m,i do p[k] = false end
      count = count + 1
    end
  end
  return count
end

local N = tonumber(arg and arg[1]) or 1
if N < 2 then N = 2 end
local primes = {}

for i=0,2 do
  local m = (2^(N-i))*10000
  io.write(string.format("Primes up to %8d %8d\n", m, nsieve(primes, m)))
end

-- Lua benchmark: nsieve-bit. Written by Mike Pall. Public domain.

local bit = require("bit")
local band, bxor, rshift, rol = bit.band, bit.bxor, bit.rshift, bit.rol

local function nsieve(p, m)
  local count = 0
  for i=0,rshift(m, 5) do p[i] = -1 end
  for i=2,m do
    if band(rshift(p[rshift(i, 5)], i), 1) ~= 0 then
      count = count + 1
      for j=i+i,m,i do
	local jx = rshift(j, 5)
	p[jx] = band(p[jx], rol(-2, j))
      end
    end
  end
  return count
end

local N = tonumber(arg and arg[1]) or 1
if N < 2 then N = 2 end
local primes = {}

for i=0,2 do
  local m = (2^(N-i))*10000
  io.write(string.format("Primes up to %8d %8d\n", m, nsieve(primes, m)))
end