Gilles Chanteperdrix wrote:
> Jan Kiszka wrote:
>> Why? It delivers us the core mechanism we need for the rest as well -
>> and it does not require fancy I-pipe hooks.
> Because relying on the vdso/vsyscall only works on x86. Whereas
> implementing clock slew down/acceleration at nucleus level and simply
> sharing data between kernel and user through the the global sem heap,
> works for all architectures.

There are three kind of archs:
 - those that already support vgettimeofday & friends (x86, powerpc,
   maybe more)
 - those that do not yet though they could (I strongly suspect arm falls
   into this category as well)
 - those that never will (due to lacking user-readable time sources)

We need temporary/permanent i-pipe workarounds for the last two, but I
see no point in complicating the first category. This design aims at a
longer term.


Siemens AG, Corporate Technology, CT T DE IT 1
Corporate Competence Center Embedded Linux

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