Optimized kernel builds: the straight dope [fp extensions]

[Christian Leber]

On Tue, Aug 15, 2006 at 01:46:14PM -0700, Matt Zimmerman wrote:
> > IMO getting rid of these optimized kernels should be done after much
> > broader testing than 2 randomly chosen desktops. Think of people using
> > encrypted filesystems, compressed filesystems, etc.
> 
> The case is already made for eliminating them, based on the maintenance
> overhead, and there currently exists no evidence whatsoever in favour of
> keeping them, though we have made some effort to collect it.  If you wish to
> contribute your own measurements, you are welcome, but hypothetical
> scenarios and arguments will not sway the decision.  This holds especially
> true for niche use cases like the ones you name; we will not hesitate to
> optimize for the common case at some small expense to scarce ones.

The only problem could come from functions like memcpy, fast_clear_page
from /arch/i386/lib/mmx.c
Benchmarking that in a complete system will be hard, i doubt that
this functions are worth it, to keep more kernels and confusing people.

The cases of some hypothetical encrypted or compressed filesystems could be
easily solved in a way like it is done for the RAID 5/6 modules. (they
benchmark for the fastest algorithm every boot)


Christian Leber

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