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Re: i486 base architecture



Dave Jones wrote:

On Sun, Nov 28, 2004 at 09:36:45PM -0500, Jeff Johnson wrote:
>And it also shouldn't surprise that there are indeed instructions that have
>crept into various packages that preven execution on i386, rdtsc in rpm (so I
>don't have to stare at gettimeofday in straces) comes to mind.

Hopefully you're checking the cpuid feature flags to make sure 'tsc'
is there first, and falling back to get_timeofday if not present ?
If not, this is horribly broken on..

- lots of 586's.
Cyrix, and early AMDs iirc didn't have TSC.
- Any CPU with errata making TSC unusable.
Winchip C6 was one such beast. (586), there may be
others too.


- Some NUMA boxes have big problems keeping TSCs
in sync, and fall back to alternative timing sources.



Yep.


Come to think of it, why is rpm needing to do this anyway ?


Because I'm ask continuosly and repeatedly Why is rpm slow? And noone is willing to hear the answer Because packages and rpm features are getting fatter and fatter.

There is one remianing (and excrutaingly painful to fix) bottleneck in rpm,
you know as
   Preparing  ============ ...

Add --stats to any command, measure your own bottlenecks. But won't work on any
of the platforms you mention above.


73 de Jeff



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