[OT] exception performance cost

[Matthias Weiss]

Hi all!

This is possibly OT, please tell me if discussion of
this is unwanted on this list.

I wanted some raw number telling me the performance difference
between a C++ code with exceptions and one with error return
code.

I wrote 3 very simple C++ programs to test it. I compiled it
with different flags and first checked the size differenz.
Using exceptions increase the file size with an amount of
6 - 10 %.

Then I checked execution time. I compiled all 3 programs with

g++-3.0 -Wall -Os -O2 -fomit-frame-pointer -march=i686 -o exception_performance3 exception_performance3.cpp

and stripped them afterwards.
I ran all 3 programs at least 5 consecutive times and calculated the average.
I used the "time" comand to measure the execution time.
The result was that using exceptions introduces less than 2 % performance loss.

Then I altered the 3 files and included 2 gettimeofday calls to measure the
ellapsed time. Surprisingly the situation flipped and now not using exceptions
costs ~3 % performance.

Has anyone an explanation for this?

I have attached the 3 source files.

matthias
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