VxWorks 6.0; RTP
Gems Bond
What's a "Real Time Process" (RTP)? Something similar to the standard
Unix-type process? Any related links on the web?
Thank you.
Alex
Each RTP process runs in its own address space. An RTP process may
contain more than one task, so in this respect it may resemble a Unix
process.
sk...@yahoo.com (Gems Bond) wrote in message news:<b5e72de9.04072...@posting.google.com>...
Gems Bond
Alex
Thanks. But, I have got a few more questions. I couldn't quite get
what the speakers were saying at the Wind River Developers'
Conference.
1) How does the scheduling take place with this new, process-cum-task,
scheme?
2) Do the device drivers continue to run in the application task
context?
3) Will there be any inter-RTP communication apart from the inter-task
communication?
Thanks again.
Guru
Below is some information I got while I attended a developer
conference recently.
>1) How does the scheduling take place with this new,
process-cum-task,
> scheme?
Nothing changed in the scheduling scheme. Scheduler is still 'task'
based. What that means is, if you have RTP1 and RTP2 in your system
and if you imagine RTP1 to have tasks say tRTP11, tRTP12 with
priorities 100 and 110 and RTP2 to have tasks say tRTP21, rRTP22 with
priorities 105 and 115, the scheduling will be in the following
order(assuming all are in ready Queue)
tRTP11 -followed by ->tRTP21 --followed by--> tRTP12 --> followed by
-->tRTP22.
The scheduling algorithm does not care which RTP the task belongs to.
At any point of time, the task with the highest priority in the ready
queue is guarenteed of the CPU time. The scheduling hence is as
efficient as in VxWorks 5.x and no compromise(Of course, there are
occasions of small overhead on house keeping if the context switch is
between the tasks of different RTPs).
> 2) Do the device drivers continue to run in the application task
> context?
No. AFAIT, The Device drivers Run in Kernel context. I am not sure, if
there are provisions to run in application context. I would consider
it rather hard to make device drivers run in user mode since they
involve closer relationship with Kernel and the hardware.
> 3) Will there be any inter-RTP communication apart from the inter-task
> communication?
WRS has got some kind of Message channel for inter-RTP communication.
> Thanks again.