[Ace-users] [tao-users] ACE (and TAO) timers for Real-Time

Mauricio =?utf-8?Q?A=2E_Araya_L=F3pez?= maray at inf.utfsm.cl
Wed Feb 27 12:17:52 CST 2008


I am trying to adapt a "time service" for a framework based on TAO to
support real-time requirements. I will start with the timer service that
is almost a simple wrapper of a ACE Timer_Queue. The question is which
POSIX syscall uses this timer queue to sleep. I was searching in the
code, but sometimes it gets too complex. Which POSIX syscall is used, 
is very important issue, because some RTOS works in real-time only for
the clock_* family (including nanosleep). Also, ACE_Time_Value class have a
resolution of microseconds, but the clock_* POSIX family have a
nanosecond resolution, so i guess that is not using this interface.

For instance, in the latest tickless Linux Kernels (with Ingo Molnar's
Real-Time patches), the clock_* family (including nanosleep), have much
better performance than the microsecond resolution calls. 

An other little question, is if the real-time performance
of the ACE Timer_Queue is ensured for distributed objects (if the
proper network is setup).

Mauricio Araya L. 
ACS-UTFSM Team Leader, cel: 0-81564903
Est. Magister en Ciencias de la Informatica UTFSM, Valparaiso, Chile
counter.li.org: #249395, http://www.inf.utfsm.cl/~maray 

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