[Texmacs-dev] General efficiency of TeXmacs

[Norbert Nemec]

Hi there,

after doing a bit more profiling, I am beginning to realize just *how* 
inefficient some of the central C++ code in TeXmacs is:

a) For the central data types (string, tree, etc), nearly all routines 
should be defined as "inline" in the header files. The cleanest and 
simplest solution that I see would be to introduce additional files like 
string.inc.hpp that contain many of the routines that are currently 
defined in string.cpp and include this at the end of string.hpp. That 
way, the header file would not become cluttered, but the compiler could 
still do heavy inlining on these routines.

b) Profiling indicates that the program spends a tremendous amount of 
time on reference counting and deallocation. Moving to a garbage 
collector would significantly simplify the code and should result in 
quite some speedup. Especially for interactive programs, garbage 
collection is the fastest memory management strategy available since all 
the collecting is simply happening in idle time and the time critical 
code does not need to worry about deallocation at all.

c) The string class is a significant bottleneck. Every time a (char*) is 
converted, the data is copied to a newly allocated location. In most 
cases, this could be avoided by simply copying a pointer. This would 
mean that the string_rep class would need to carry a flag on whether the 
space is "owned" (and should be deallocated) or just "borrowed". I 
certainly is a non-trivial task to sort this out, but I believe it would 
be the single-most-rewarding detail in optimizing for performance.

... just my analysis for the moment. I know that it would mean 
significant work to work on any of this...

Greetings,
Norbert