Re: Why is VC++ STL so slow?
"David Alasiga" <dialectics@yahoo.com> wrote in message
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"Andrew Koenig" <ark@acm.org> wrote in message
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"David Alasiga" <dialectics@yahoo.com> wrote in message
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g++ linux version runs 80% fast than VC++ version
and g++ Cygwin version (running on windows) runs 50% fast than VC++
version.
Could it be that you are running VC++ in debug mode?
No. I am running VC++ in release mode. I think something definitely
wrong with the implementation of set and map. I used a set to insert
some items and do some searching. However, the set is so slow that I
have to use a vector then sort the vector instead of using set. Vectors
are easy to be implemented but sets and maps are implemeted using some
kind of balanced tree. In theory, the performance of set should be
better than vector for searching. But in my case, the vector is far
better than the set. Then I have the performance issue with the map.
That forces me to think that the VC++ STL has fundamental problems.
VC++ 2005 (V8) also has extensive additional checking of iterators
*that remains on in release mode* unless you make an effort to turn
it off. This was a Microsoft decision, to favor safety over performance
by default. Other people have commented on such loss of performance in
migrating to V8.
P.J. Plauger
Dinkumware, Ltd.
http://www.dinkumware.com
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