Re: How fast is LuaJIT supposed to be?

[Steve Litt <slitt@...>]

On Friday 21 January 2011 01:52:40 Alexander Gladysh wrote:
> On Fri, Jan 21, 2011 at 09:47, Steve Litt <slitt@troubleshooters.com> wrote:
> > A few weeks ago I wrote a Lua prime number generator. Today, to test Lua
> > 5.1.4 vs LuaJIT 1.1.6 I ran the prime numbers between 1 and 50 million,
> > writing all numbers to /dev/null to minimize I/O time. Lua took typically
> > around 48 seconds and LuaJIT took around 34 seconds. Is this typical of a
> > CPU/memory bound process?
> 
> Why do you try LJ 1.1.6? Try LuaJIT 2! :-)

Is it significantly faster than 1.1.6? I just took the stable one.

> 
> Also, you may want to show us the benchmark code.

Attached. Please don't laugh too hard -- I'd had about 3 days of Lua 
experience when I wrote it. Writing that program so easily and having it run 
so quickly was one of the things that made me decide to look more deeply into 
Lua.

In case your list doesn't allow attachments, I've printed it at the bottom of 
this email.

Thanks

SteveT

Steve Litt
Recession Relief Package
http://www.recession-relief.US
Twitter: http://www.twitter.com/stevelitt

#!/usr/bin/lua

--[[
Copyright (c) 2010 by Steve Litt

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in
all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
THE SOFTWARE.
]]


function mark_multiples(primes)             
	local multiple=primes["candidate"]
	while multiple <= primes["upto"] do
		multiple = multiple + primes["candidate"]
		-- print(string.format("dia multiple=%d", multiple))
		primes[multiple] = 0
	end
end


function find_next_candidate(primes)             
	primes["candidate"] = primes["candidate"] + 1
	while primes[primes["candidate"]] == 0 do
		primes["candidate"] = primes["candidate"] + 1
	end

end


function print_primes(primes)
	for i=1, primearray["upto"] do
		if primearray[i] == 1 then
			print(i)
		end
	end
end


function print_array(primes)
	for i=1, primearray["upto"] do
		print(string.format("%d     %d", i, primearray[i]))
	end
end


function mark_all_as_prime(primes)
	for i=1, primearray["upto"] do primearray[i]=1 end
end


function main()
	primearray={
		upto=arg[1] + 0,
		candidate=2,
		maxcandidate=math.sqrt(arg[1])
	}

	mark_all_as_prime(primes)

	while primearray["maxcandidate"] > primearray["candidate"] do
		mark_multiples(primearray)             
		find_next_candidate(primearray)             
	end

	print_primes(primearray)
	-- print_array(primearray)
end

main()

#!/usr/bin/lua

--[[
Copyright (c) 2010 by Steve Litt

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in
all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
THE SOFTWARE.
]]


function mark_multiples(primes)             
	local multiple=primes["candidate"]
	while multiple <= primes["upto"] do
		multiple = multiple + primes["candidate"]
		-- print(string.format("dia multiple=%d", multiple))
		primes[multiple] = 0
	end
end


function find_next_candidate(primes)             
	primes["candidate"] = primes["candidate"] + 1
	while primes[primes["candidate"]] == 0 do
		primes["candidate"] = primes["candidate"] + 1
	end

end


function print_primes(primes)
	for i=1, primearray["upto"] do
		if primearray[i] == 1 then
			print(i)
		end
	end
end


function print_array(primes)
	for i=1, primearray["upto"] do
		print(string.format("%d     %d", i, primearray[i]))
	end
end


function mark_all_as_prime(primes)
	for i=1, primearray["upto"] do primearray[i]=1 end
end


function main()
	primearray={
		upto=arg[1] + 0,
		candidate=2,
		maxcandidate=math.sqrt(arg[1])
	}

	mark_all_as_prime(primes)

	while primearray["maxcandidate"] > primearray["candidate"] do
		mark_multiples(primearray)             
		find_next_candidate(primearray)             
	end

	print_primes(primearray)
	-- print_array(primearray)
end

main()