Compilation time (was Re: GCC 3.3)

[Daniel Berlin]

>
> I also agree we should make compilation time a major goal for 3.4.  
> One implication: if this is a major goal, then it's too important to 
> be left just to the people who care about compilation time.  One thing 
> we've observed at Apple, and I hope people on this list have noticed 
> it too, is that performance just leaks away if you're not looking at 
> it.  Everybody should be thinking about the performance implications 
> of their changes, and everyone should be measuring.  Finally, 
> everybody should be concerned about small regressions, not just large 
> ones.  A 2% performance regression may not seem like much, but if you 
> check in a change that causes a 2% regression then you've just put a 
> new work item on someone else's queue: find another change to get back 
> that lost time.  It doesn't take very many small regressions to make 
> up a noticeable degradation.
>

While we already have people doing nightly testing of performance of 
generated code, maybe we need some nightly testing of compilation speed 
on some representative set of code.
A weekly nag report that tells us how much performance has 
improved/degraded on the various tests that week/month/since last 
release would be nice, too.

> 			--Matt
>