A question on kernel clock:

Wolfgang Denk wd at denx.de
Wed Dec 31 05:49:46 EST 2003

Dear John,

in message <000501c3cec2$130dbab0$b702a8c0 at newrock2> you wrote:
> The processor I mentioned is MPC82xx. Now, I have kernel from kernel.org

[I guessed that from the ...BRG8 part.]

> run on the board. But, my "nsleep()" is not exactly. So, I want to
> realize the timer mechanism of Linux used.

> (1) which timer is used for nsleep?

I have not the slightest idea. I don't know of any  standard  funtion
with that name - neither in user space nor in kernel code.

> (2) can udelay() be changed to be preempted by other process?

That makes little sense. If you allow to run other prcesses inbetween
you will have  looong  delays  -  udelay()  was  not  made  for  such
purposes,  but  for  very  short delays (as the name suggests: in the
range of a few microseconds).

> (3) which is good choice for Kernel timeslice?

What's wrong with the standard 10 ms ?

> Additional, could we develop a bootloader like vxworks' bootloader? (
> vxworks bootloader is a little vxworks, I think.)

Of course you can. But what for? If you like the VxWorks boot loader,
then use it. If you like something more powerful, use U-Boot.

Best regards,

Wolfgang Denk

Software Engineering:  Embedded and Realtime Systems,  Embedded Linux
Phone: (+49)-8142-4596-87  Fax: (+49)-8142-4596-88  Email: wd at denx.de
This all sounds complicated, but it mostly does excatly what you  ex-
pect. It's just difficult for us to explain what you expect...
                       - L. Wall & R. L. Schwartz, _Programming Perl_

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