How to detect whether CPU is idle?
Ben
I am starting a device driver which will layer on top of the current
disk deivce drivers.When the CPU is idle,my driver will wake up otherwise it
will keep sleeping.So I need an API/function to detect the CPU is idle or
not from my driver code.Anyone can give some hints?Thanks in advance.
---Ben
fvw
Leave the scheduling to the system. Just go to nice +19, that way you'll only
get cpu time when the cpu is idle (well, not completely true, but the little
non-idle cpu time you get is negligable).
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Frank v Waveren
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ri...@no-annexia-spam.org
: Hi,there,
: I am starting a device driver which will layer on top of the current
: disk deivce drivers.When the CPU is idle,my driver will wake up otherwise it
: will keep sleeping.So I need an API/function to detect the CPU is idle or
: not from my driver code.Anyone can give some hints?Thanks in advance.
Why do you want to do this? If you have some background
processing it to do, it might be better to do it in
a daemon in userspace.
Rich.
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--- Original message content Copyright © 1999 Richard Jones ---
Peter Samuelson
> It is a driver .. good luck with trying to re-nice a kernel driver.
That is what kernel threads are for. So that you can play with the
process context state of what is otherwise just a driver.
Peter
Juergen Heinzl
>In <86sh8q$koj$1...@ron.uri.edu>, benlin...@yahoo.com wrote:
>>Hi,there,
>> I am starting a device driver which will layer on top of the current
>>disk deivce drivers.When the CPU is idle,my driver will wake up otherwise it
>>will keep sleeping.So I need an API/function to detect the CPU is idle or
>>not from my driver code.Anyone can give some hints?Thanks in advance.
>
>get cpu time when the cpu is idle (well, not completely true, but the little
>non-idle cpu time you get is negligable).
It is a driver .. good luck with trying to re-nice a kernel driver.
You might start here ...
/usr/src/linux/init/main.c
... as there is an idle thread and take a look into the scheduler
code too. AFAIK though there cannot even be a API function as the
kernel is using the HALT instruction so your best bet might be
a 08/15 driver.
I am not going to ask why you want to do that, hope this is okay ;)
Juergen
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fvw
>It is a driver .. good luck with trying to re-nice a kernel driver.
Oh, my bad. sorry.