Re: Why is this slow?

["Joshua Ritter" <ritterjoshua@...>]

Hm... I would guess it has to do with the amount of memory being allocated
and freed in the Lua version...
Does your python version have an equivalent:

local c ={}
c.peer = caller

I am also skeptical of forcing the garbage collection like this...

Of course I am darned new to Lua myself!

-J


----- Original Message -----
From: "Jakab, Steve" <sjakab@verant.com>
To: "Multiple recipients of list" <lua-l@tecgraf.puc-rio.br>
Sent: Wednesday, February 07, 2001 9:41 AM
Subject: Why is this slow?


> 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:
>
> int getData(lua_State *L)
> {
> // 1st argument = calling object pointer (userdata)
> // 2nd argument = data name (string)
> TestObject *object = (TestObject *)lua_touserdata(L, 1);
> const char *varname = lua_tostring(L, 2);
>
> int value = object->GetData(varname);
>
> // push the return value on the stack
> lua_pushnumber(L, value);
>
> return 1;
> } // getData
>
> int setData(lua_State *L)
> {
> // 1st argument = calling object pointer (userdata)
> // 2nd argument = data name (string)
> // 3rd argument = data value (number)
> TestObject *object = (TestObject *)lua_touserdata(L, 1);
> const char *varname = lua_tostring(L, 2);
> int value = (int)lua_tonumber(L, 3);
>
> object->SetData(varname, value);
>
> return 0;
> } // setData
>
> void runtest(TestObject *obj)
> {
> int oldtop = lua_gettop(L);
> int result = lua_dofile(L, "TestDataPass.lua");
> if (result != 0)
> return;
>
> // call the constructor
> lua_getglobal(L, "TestDataPass");
> lua_pushuserdata(L, obj);
> result = lua_call(L, 1, 1);
> if (result != 0)
> {
> lua_settop(L, oldtop);
> return;
> }
> // get the reference to the returned class (locking it so it won't
> be
> // garbage collected)
> int classRef = lua_ref(L, 1);
> // free the class reference
> lua_unref(L, classRef);
> } // runtest
>
> TestObject is just a structure that maps a string to an integer.
>
> 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? When I tried a test just calling a do-nothing
> function in Lua, it beat Python easily, so I assume that it's the
paramater
> passing that's slowing Lua down.
>
> -Steve Jakab
> Verant
>
>