On Sun, Jul 29, 2001 at 10:55:23AM +0530, Chandu Reddy K wrote:
>
> HI
> All
> I have few doubts related to Threads.
> currently i am using linux 2.2.18 + rtlinux 3.0
>
> 1) Is there any limit on Number threads one can use simulatenously..
> with out any performance degradation of the system,
Each additional thread costs memory and each additional context switch
costs time. Threads make designs simpler and more robust, but cost
computing resources. But see below.
> 2) And in my application if therere is a need to maintaion different
> timing
> values at different situations..
> whether there is any other method to mainatin this ,
> with out creating threads for each timing values.
> i felt having too many threads defenitely leads to schedulling
> jitter.
>
> any comments on these from mailing lists???
This second thing is too vague.
>
> 3) one more senario is suppose if my applivcation requires 4 different
> kinds timers
> for different situations.. Currenlty i can go for 4 threads ( 3
> minute threads, 1 second
> thread)
> among these 3 threads neads to be invoked after m1,m2,m3 minutes
> and another
> 4th one needs to be invoked after few seconds.
4 threads is nothing.
> and once these are invoked depending up on my controler module
> requiremnt,
> my application will take acttions and again make the threads
> periodic
> according to new timings.
>
> if this is the case, which of the following methods
> are efficient.......
>
> a) having 4 threads
>
> b) having single thread, it will wake up for every second...
> in this thread it self i will handle minute timimg also
Depends on the application.
>
>
>
> or any other method which suits this..
>
> any more suggestions/help from list..............
>
>
> advance thanks.
> chandu
>
> -----Original Message-----
> From: Tomasz Motylewski [mailto:[EMAIL PROTECTED]]
> Sent: Friday, July 27, 2001 7:17 PM
> To: Chandu Reddy K
> Cc: [EMAIL PROTECTED]
> Subject: Re: [rtl] Regd Shared Memory and function pointers
>
>
> > i will store a function pointer of a function d
> > here i faced probem that i am not able to access function pointer
> > in linux appl.
> > its giving compiler error...
> > that functionname(), ....
> >
> > whether doing this way is correct or not ???
>
> Not. Kernel is different adress space, and your user program is not linked
> with it.
>
> Use indexes (like 1,2,3,4,5,6...) instead of pointers.
>
> You can set up in the kernel array of function pointers:
>
> int (*(functions[NNN]))() = { func1, func2, func3, ... };
>
> functions[i](); <- call this way.
>
> --
> Tomek
>
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