Re: [jamboost] class.jam performance issues

From: Vladimir Prus (ghost_at_[hidden])
Date: 2002-07-22 12:10:04

Vladimir Prus wrote:

> This is very slow! It essentially means that if I switch from using jam
> list to using contaner.vector in one place, I'll have 100x slowdown.
> Actually... it seems worse than that: each construction of class causes a
> call to BACKTRACE and that rule returns the list of all stack frames -- I
> suspect a quadratic running time is possible.

And regardless of way we use classes, quardratic running time seems terrible 
idea to me. I've added a new optional parameter, 'levels' to the BACKTRACE 
rule. Now class.jam calls it as [ BACKTRACE 1 ], so there's no more quadratic 
time. For my test case, this reduces the running time from
6.3/5.3 secons (real/user time) to 4/3.4
Gonna commit the change soon.

- Volodya