Re: RTL scheduler
| Newsgroups | gmane.linux.real-time.rtlinux.general |
|---|---|
| Message-ID | <[email protected]> |
The basic scheduler in RTLinuxFree is pure priority and it has no concept of deadline. If thread X starts at time t1 and is scheduled to run every 100 microseconds then either it will finish in time or it will not. If it does not finish in time, it will continue to run until it either waits for a new deadline or it is preempted by a higher priority thread. What semantics do you want? It's easy, for example, to define for each thread X a thread X' run at priority(X)+1 (you need to leave the right gaps) and then schedule X' to start at the moment X is supposed to be done (deadline X). If X is not done, X' can kill it or turn the power off or start a third thread or print a diagnostic or . On Fri, Nov 26, 2004 at 05:30:24PM -0500, Santanu Chatterjee wrote: > Hi, > I am new to the world of RTLinux and I was wondering if anyone > could point me to some comprehensive tutorial on RTLinux scheduler. I > am trying to figure out how RTLinux scheduler deals with the deadline. > For example, let us consider that we are running a real-time > application which will read data from a port at each 100 micros. That > means if that code starts at time t1, it'll have to finish before > t1+100 and have to be scheduled to run again at t1+100. > > What happens if it can't finish before t1+100? At that point > there'll be new set of data on the port to be read while the old data > is still being read by real-time application. Does RTLinux stops the > currently executing application and does a fresh start for the new set > of data? I was doing some research regarding scheduling in real-time > systems. I used QNX before. I know that QNX works that way ( stops old > process which is not finished within deadline and starts a new > process). > > Any input on this will be highly appreciated. > > thanks, > santanu > _______________________________________________ > Rtl mailing list > [email protected] > http://www2.fsmlabs.com/mailman/listinfo/rtl _______________________________________________ Rtl mailing list [email protected] http://www2.fsmlabs.com/mailman/listinfo/rtl