Re: Why is this slow?
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- Subject: Re: Why is this slow?
- From: Edgar Toernig <froese@...>
- Date: 2001年2月09日 06:49:28 +0100
Hi,
"Jakab, Steve" wrote:
>
> When doing benchmark tests between Lua and Python, Lua beat it on almost
> every test. However, it was considerably slower on a test of passing data
> between Lua and C. Here is the Lua code:
>
> function TestDataPass(caller)
> local c = {}
> c.peer = caller
>
> value = getData(c.peer, "testdata")
> setData(c.peer, "testdata", value + 1)
>
> return c
> end
>
> Here is the C code:
> [...]
>
> void runtest(TestObject *obj)
> {
> int oldtop = lua_gettop(L);
> int result = lua_dofile(L, "TestDataPass.lua");
> if (result != 0)
>[...]
> I was able to call the runtest function around 30,000 times in 10 seconds,
> but similar test using Python ran 500,000 times in 10 seconds. Am I doing
> something wrong in my calls?
They main performance killer is the lua_dofile(). Did you really want
to compile the testfile for each iteration of your test (3000/s)? You
will not be testing data passing put compilation speed :-) Do it once
before you call runtest the first time and I guess you'll already beat
Python ;-)
And then there's the Lua code itself. I do not know if you really want
to create a new table each time TestDataPass() is called, but the line
"local c = {}" takes approximately half of the time. And at last, you
should make the variable "value" a local. They are faster than globals.
Ciao, ET.