Am 21.05.2014 09:31, schrieb Noel Grandin:
> On 2014-05-20 21:11, Karsten Blees wrote:
>> * implement Mac OSX version using mach_absolute_time
>>
>>
>
>
> Note that unlike the Windows and Linux APIs, mach_absolute_time does not do
> correction for frequency-scaling
I don't have a MAC so I can't test any of this, but supposedly
mach_timebase_info() returns the frequency of mach_absolute_time(), so you
could do similar frequency-scaling as I do for Windows with
QueryPerformanceFrequency().
> and cross-CPU synchronization with the TSC.
>
The TSC is synchronized across cores and sockets on modern x86 hardware [1] (at
least since Intel Nehalem, i.e. all Core i[357] processors). On older machines,
I would expect the OS API to choose a more appropriate time source, e.g. the
HPET. I'm not proposing to use asm("rdtsc") or anything like that...
[1]
https://software.intel.com/en-us/articles/best-timing-function-for-measuring-ipp-api-timing
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