Re: [RFC 00/15] x86_64: Optimize percpu accesses

From: Ingo Molnar
Date: Wed Jul 09 2008 - 17:13:30 EST



* Mike Travis <travis@xxxxxxx> wrote:

> After that is taken care of, I'll start regression testing earlier
> compilers. I think someone mentioned that gcc-2.something was the
> minimum required...?

i think the current official minimum is around gcc-3.2 [2.x is out of
question because we have a few feature dependencies on gcc-3.x] - but i
stopped using it because it miscompiles the kernel so often. 4.0 was
really bad due to large stack footprint. The 4.3.x series miscompiles
the kernel too in certain situations - there was a high-rising
kerneloops.org crash recently in ext3.

So in general, 'too new' is bad because it has new regressions, 'too
old' is bad because it has unfixed old regressions. Somewhere in the
middle, 4.2.x-ish, seems to be pretty robust in practice.

Ingo
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