Re: [luabind] LUA profiler and luabind performance

[Dmitriy I. <ias...@gs...>]

Hello,

DI> we've implemented simple LUA profiler using LUA and found an
DI> interesting thing : a lot of time is used by the unknown C function
DI> (i.e. its string description is empty) During investigation of this
DI> spy function we found that each access to the "self" variable
DI> generates call of this unknown function. Therefore several questions
DI> arise :

DI> 1. Can you associate with this function some reasonable class or/and
DI> class instance debug information? (since, we found that even parsing
DI> class method generates that call)

DI> 2. 37% of the time being used by scripts they spend inside this
DI> function - is it possible to optimize self usage from the C++ part?

DI> 3. Is there any techniques which can make our LUA code more optimal?
DI> We tried to declare local variable and assign self to it, but it
DI> didn't help. How can we reduce the number of accesses to self?

There is a question about luabind::detail::class_rep implementation.

file luabind/detail/class_rep.hpp
..
line 368:
                // datamembers, some members may be readonly, and
                // only have a getter function
                std::map<const char*, callback, ltstr> m_getters;
                std::map<const char*, callback, ltstr> m_setters;
..

What is the reason in using so inefficient structure for the members
which are used so often? Is there any drawbacks in using native LUA
tables instead, which are greatly optimized for strings? Each access
to class instance like "self.a = 1" contains at least two searches
over that map, i.e. several string comparisons, which are not fast for
sure.

-- 
Best regards,
 Dmitriy                            mailto:ias...@gs...