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Re: i486 base architecture



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.

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

		Dave


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