Hello,
On 10/21/2014 07:33 PM, 王硕 wrote:
Dear Norman and all Genodians,
the Genode OS framework is neither Norman's exclusive project, nor limited to the team working at Genode Labs, but at least meant as an open source community project. Although, Norman and the team at Genode Labs have the greatest influence on the project, and are mostly competent contacts, with this mailing list you address *all* Genode developers and enthusiasts. So _please_: avoid addressing people personally in the first place.
I want to obtain real-world date and time in Genode (base-foc), so would you like to tell me how to achieve it. Rtc is too slow, and Rdtsc can't obtain real time.
When you say RTC is too slow, what drift did you perceived?
Joking apart, your problem is a basic problem in computer science not limited, or special with respect to Genode. I assume with "RTC is too slow" you meant that reading the RTC every time you need a timestamp is to expensive. If you look at existent systems like for instance Linux, the problem is solved in the following way: Calendar time is read exactly once while booting, and stored in a variable. From that on another less expensive system timer is used to add periodically wall-clock time to the initial time-stamp.
To break it down to your problem:
* Initially read the RTC time, as well as the RDTSC * Whenever you want to read the current time, read the RDTSC, and add the difference between the actual and the last RDTSC value to your stored calendar time, and you are done
Regards Stefan
Shuo Wang, University of Chinese Academy of Sciences.
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