Re: Navie question about profile

Clemens Eisserer wrote:
> Just for fun I did some profiling using oprofile or a firefox-build
> (2.0.6) compiled built with debug enabled

For what it's worth, that usually gives incorrect numbers for two reasons:

1)  Unless you also did --enable-optimize, compiler optimizations
     (e.g. method inlining) are disabled.
2)  There are debug-only data structure verifications that make some
     algorithms actually have different computational complexity in debug
     builds (e.g. an O(N) algorithm in non-debug builds might become O(N^2)
     in a debug build because of O(N) code that checks intermediate stages
     of the computation).

> This is what I got:
> 197255   10.2989  libgklayout.so           libgklayout.so
> nsVoidArray::Count() const
> 166882    8.7131  libgklayout.so           libgklayout.so
> nsCellMap::GetDataAt(nsTableCellMap&, int, int, int)
...
> Is the Count() method really that slow, or am I getting wrong results
> because I am using a build compiled with debug on?

Count() is inlined in non-debug builds, and GetDataAt() (which is probably your 
major caller of Count()) gets called more in debug builds because of some table 
layout verification code.  So I think you're hitting both of the issues I 
describe above.

-Boris