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Re: program executin times differ between gcc versions
And what about volatile variables?
If you have variables that might be modified by multiple threads you
should declare them as volatiles in order to prevent compiler
optmization and wrong execution.
Tim Prince wrote:
Joel Dice wrote:
On Thu, 1 Nov 2007, Paul Moore wrote:When hotspots occur in libraries, gprof is satisfactory only with
static linking. Library questions seem unlikely to be relevant in
Using optimization flags is not possible due to the fact that large
parts of the application failed in -O test runs and would need to be
fixed/tested extensively first. Profiling with -pg/gprof has not been
produced usable results as shared libraries are not being tracked.
In my experience, OProfile (oprofile.sourceforge.net) is much better
than gprof at revealing the hotspots in my programs, including time
spent in shared libraries. I strongly recommend it.
That's for sure. gcc is unlikely to break reliable code with
optimization, unless -ffast-math is set.
OTOH, I would worry more about correctness than performance at this
point if the code breaks with optimization turned on.
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