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Re: [PATCH] Add tree rest of compilation timevar
On Wed, 2004-12-29 at 11:46 -0800, Matt Austern wrote:
> Actually, I've got a more general question: do people find this timevar
> stuff useful in understanding compilation performance? If so, what do
> they find it useful for? If we have a clearer idea of the purpose of
> this feature, we might get some better guidance on how to change it.
In find it useful at a macro-level -- ie, it's useful in spotting
performance behavior which is way outside the bounds of normal.
It's also been useful to track how a change impacts performance without
resorting to profiling. ie, if I make a change which I expect to result
in a significant improvement, I can see it in the timevars.
I don't find them useful to actually understand *why* any particular
part of the compiler is mis-behaving or for tracking one or more changes
which should have small performance improvements.
Jeff