Hi, Does the OS have separate stack area for itself(operating system) and separate stack area for the application ? Or Does the stack area of the application will be part of the stack(bigger stack) of the Operating System ? I do not find Clear information w.r.t this on the internet. Any ideas ? Can somone tell me w.r.t a specific OS & application ? Thx in advans, Karthik Balaguru
Stack - OS and Application
Started by ●October 24, 2007
Reply by ●October 24, 20072007-10-24
On Wed, 24 Oct 2007 06:47:10 -0700, karthikbalaguru wrote:> Hi, > > Does the OS have separate stack area for itself(operating system) and > separate stack area for the application ? > Or > Does the stack area of the application will be part of the > stack(bigger stack) of the Operating System ? > > I do not find Clear information w.r.t this on the internet. Any > ideas ? > Can somone tell me w.r.t a specific OS & application ? >What an OS does with stacks depends on the OS. It's pretty much necessary to maintain a stack for each thread of execution, so you can count on that happening. Some of the really small microkernels (Micro-C/OS for example) don't really maintain an independent thread other than the idle thread; other OS's (like Linux or Windows) may have many applications and drivers, each with their own tasks, running in the background. -- Tim Wescott Control systems and communications consulting http://www.wescottdesign.com Need to learn how to apply control theory in your embedded system? "Applied Control Theory for Embedded Systems" by Tim Wescott Elsevier/Newnes, http://www.wescottdesign.com/actfes/actfes.html
Reply by ●October 24, 20072007-10-24
In article <1193233630.809609.95000@z24g2000prh.googlegroups.com>, karthikbalaguru <karthikbalaguru79@gmail.com> writes: |> |> Does the OS have separate stack area for itself(operating system) and |> separate stack area for the application ? |> Or |> Does the stack area of the application will be part of the |> stack(bigger stack) of the Operating System ? Either, both or neither, depending. I have seen all of those. |> I do not find Clear information w.r.t this on the internet. Any |> ideas ? |> Can somone tell me w.r.t a specific OS & application ? Look, you are likely to get confused if you proceed like this, and will certainly annoy people. I recommend finding a book that gives an introduction to operating system design, and reading it. Ask on comp.theory for book recommendations. And don't post basic questions to so many groups. Regards, Nick Maclaren.
Reply by ●October 24, 20072007-10-24
Tim Wescott wrote:>>Does the OS have separate stack area for itself(operating system) and >>separate stack area for the application ? >>Or >>Does the stack area of the application will be part of the >>stack(bigger stack) of the Operating System ? >> > > What an OS does with stacks depends on the OS. It's pretty much necessary > to maintain a stack for each thread of execution, so you can count on that > happening. Some of the really small microkernels (Micro-C/OS for example) > don't really maintain an independent thread other than the idle thread;In our proprietary RTOS HALOS, I also maintain a separate stack for all of the interrupt system. Thus the nested interrupts do not waste the stack space of the tasks; also the interrupt stack is located in the fast memory area, so the response time is better.>> other OS's (like Linux or Windows) may have many applications and drivers, >> each with their own tasks, running in the background.If you have a full blown MMU and non-RTOS desktop OS, this is a different story. Vladimir Vassilevsky DSP and Mixed Signal Design Consultant http://www.abvolt.com
Reply by ●October 24, 20072007-10-24
"karthikbalaguru" <karthikbalaguru79@gmail.com> wrote in message news:1193233630.809609.95000@z24g2000prh.googlegroups.com...> Hi, > > Does the OS have separate stack area for itself(operating system) and > separate stack area for the application ? > Or > Does the stack area of the application will be part of the > stack(bigger stack) of the Operating System ?Any particular OS you are thinking of? See www.freertos.org/implementation for some general info. -- Regards, Richard. + http://www.FreeRTOS.org 13 official architecture ports, 1000 downloads per week. + http://www.SafeRTOS.com Certified by T�V as meeting the requirements for safety related systems.
Reply by ●October 24, 20072007-10-24
Vladimir Vassilevsky wrote:> > > Tim Wescott wrote: > > >>> Does the OS have separate stack area for itself(operating system) and >>> separate stack area for the application ? >>> Or >>> Does the stack area of the application will be part of the >>> stack(bigger stack) of the Operating System ? >>> >> >> What an OS does with stacks depends on the OS. It's pretty much >> necessary >> to maintain a stack for each thread of execution, so you can count on >> that >> happening. Some of the really small microkernels (Micro-C/OS for >> example) >> don't really maintain an independent thread other than the idle thread; > > > In our proprietary RTOS HALOS, I also maintain a separate stack for all > of the interrupt system. Thus the nested interrupts do not waste the > stack space of the tasks; also the interrupt stack is located in the > fast memory area, so the response time is better. >You can do this with Micro-C/OS-II as well, although you have to add it in yourself. It's a good thing if you have a lot of tasks in a memory-constrained system: instead of having to add space for the interrupts everywhere, you only need it in one spot.> >>> other OS's (like Linux or Windows) may have many applications and >>> drivers, >>> each with their own tasks, running in the background. > > If you have a full blown MMU and non-RTOS desktop OS, this is a > different story.Even with an MMU a separate thread needs its own stack space. Its existence may be buried underneath a pile of other code, but it'll still be there. -- Tim Wescott Wescott Design Services http://www.wescottdesign.com Do you need to implement control loops in software? "Applied Control Theory for Embedded Systems" gives you just what it says. See details at http://www.wescottdesign.com/actfes/actfes.html
Reply by ●October 24, 20072007-10-24
> Even with an MMU a separate thread needs its own stack space. Its > existence may be buried underneath a pile of other code, but it'll still > be there.Depending on how you define a thread, I would add "*in a pre-emptive system* - a separate thread needs its own stack space". Cooperative threads can share a stack. FreeRTOS.org has both. -- Regards, Richard. + http://www.FreeRTOS.org 13 official architecture ports, 1000 downloads per week. + http://www.SafeRTOS.com Certified by T�V as meeting the requirements for safety related systems.
Reply by ●October 24, 20072007-10-24
In article <I9LTi.36253$c_1.31227@text.news.blueyonder.co.uk>, "FreeRTOS.org" <noemail@address.com> writes: |> |> > Even with an MMU a separate thread needs its own stack space. Its |> > existence may be buried underneath a pile of other code, but it'll still |> > be there. |> |> Depending on how you define a thread, I would add "*in a pre-emptive |> system* - a separate thread needs its own stack space". Cooperative threads |> can share a stack. FreeRTOS.org has both. Commonly called coroutines. And they can all share space if they use the heap to get each frame, preemptively or not. And you can have threads that have no associated storage. And .... Regards, Nick Maclaren.
Reply by ●October 25, 20072007-10-25
"Tim Wescott" <tim@seemywebsite.com> wrote in message news:ZJSdnYF_kM3_5YLanZ2dnUVZ_q3inZ2d@web-ster.com...> Vladimir Vassilevsky wrote: > > > > > > In our proprietary RTOS HALOS, I also maintain a separate stack for all > > of the interrupt system. Thus the nested interrupts do not waste the > > stack space of the tasks; also the interrupt stack is located in the > > fast memory area, so the response time is better. > > > You can do this with Micro-C/OS-II as well, although you have to add it > in yourself.Just another illustration that mucos is a toy and its architecture is miserable.> It's a good thing if you have a lot of tasks in a > memory-constrained system: instead of having to add space for the > interrupts everywhere, you only need it in one spot.Another advantage is that the interrupt stack is located in the fast memory on chip, so the interrupt latency is low and independent of the state of the cache and the timing of the bus.> >>> other OS's (like Linux or Windows) may have many applications and > >>> drivers, > >>> each with their own tasks, running in the background. > > > > If you have a full blown MMU and non-RTOS desktop OS, this is a > > different story. > > Even with an MMU a separate thread needs its own stack space. Its > existence may be buried underneath a pile of other code, but it'll still > be there.The MMU is the good thing to have. It solves so many problems. Even a 286-like MMU is a great aid to the multitasking system. Vladimir Vassilevsky DSP and Mixed Signal Consultant www.abvolt.com
Reply by ●October 29, 20072007-10-29
Nick Maclaren wrote:> In article <1193233630.809609.95000@z24g2000prh.googlegroups.com>, > karthikbalaguru <karthikbalaguru79@gmail.com> writes: > |> > |> Does the OS have separate stack area for itself(operating system) and > |> separate stack area for the application ? > |> Or > |> Does the stack area of the application will be part of the > |> stack(bigger stack) of the Operating System ? > > Either, both or neither, depending. I have seen all of those. > > |> I do not find Clear information w.r.t this on the internet. Any > |> ideas ? > |> Can somone tell me w.r.t a specific OS & application ? > > Look, you are likely to get confused if you proceed like this, and > will certainly annoy people. > > I recommend finding a book that gives an introduction to operating > system design, and reading it. Ask on comp.theory for book > recommendations. > > And don't post basic questions to so many groups. > > > Regards, > Nick Maclaren.Ditto....Do your own homework....Cheating is not allowed... -J
