[ECOS] Add new class to the scheduler file

[ECOS] Add new class to the scheduler file

[Nodir Kodirov]

Hello eCos community!

I think regular members of the community already know that I am
working on EDF scheduler for eCos. I have some positive results far
now, but still they are far from being complete. This time I need to
add new class to my EDF scheduler source code. I faced application
compile & link problem on this, below is the description of what I
did.

My aim is to store "millisecond per system tick" as a static member of
some "general info class". Thus, I put this code:
> class Cyg_Sys_Gen_Info
> {
> public:
> 	static long ms_per_sys_tick;
> };
to packages/kernel/v3_0/include/edf.hxx

And this piece:
> Cyg_Sys_Gen_Info::Cyg_Sys_Gen_Info()
> {
>	CYG_REPORT_FUNCTION();
>	// some code here
>	CYG_REPORT_RETURN();
> }
to packages/kernel/v3_0/src/sched/edf.cxx. Next, I want to access it
as Cyg_Sys_Gen_Info::ms_per_sys_tick (from edf.cxx file). I am able to
successfully build eCos library, but at the time of application
compile & link it gives me an error:
> undefined reference to `Cyg_Sys_Gen_Info::ms_per_sys_tick'

So, now I was thinking, perhaps I should register my Cyg_Sys_Gen_Info
class in somewhere else as well. As I did register all of my scheduler
member variables in kapidata.h some time ago. Is there any evidence?

Thanks in advance,
Nodir.

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[ECOS] Re: Add new class to the scheduler file

[John Dallaway]

Hi Nodir

Nodir Kodirov wrote:

> I think regular members of the community already know that I am
> working on EDF scheduler for eCos. I have some positive results far
> now, but still they are far from being complete. This time I need to
> add new class to my EDF scheduler source code. I faced application
> compile & link problem on this, below is the description of what I
> did.
> 
> My aim is to store "millisecond per system tick" as a static member of
> some "general info class".

You really should not be concerned with time except at the level of the
system tick within the kernel. Any time-related scheduling constraints
should be expressed in ticks. Why do you need to know time in milliseconds?

Apologies for not replying sooner. I missed your e-mail for some reason.

John Dallaway
eCos maintainer

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[ECOS] Re: Add new class to the scheduler file

[Nodir Kodirov]

Hello Mr. John!

> ...Any time-related scheduling constraints should be expressed in ticks...
This is what I did as a solution. I changed my approach to get job
done and now it is alright! As you told, I used only system clock
ticks, thus didn't need in Milli seconds.

I appreciate you response, thank you very much!
Regards,
Nodir.

On 12 May 2010 18:00, John Dallaway wrote:
Hi Nodir


Nodir Kodirov wrote:

> My aim is to store "millisecond per system tick" as a static member of
> some "general info class".

You really should not be concerned with time except at the level of the
system tick within the kernel. Any time-related scheduling constraints
should be expressed in ticks. Why do you need to know time in milliseconds?

John Dallaway
eCos maintainer

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Before posting, please read the FAQ: http://ecos.sourceware.org/fom/ecos
and search the list archive: http://ecos.sourceware.org/ml/ecos-discuss