Florin Malita wrote:
On Thu, 22 Sep 2005 10:48:24 -0300
sauro <sauro@xxxxxxxxxxx> wrote:
I would like to get, from userland, the results of a function that is
only avaiable from kernel space. (get_cycles, to be exact)
What is the easiest way to do it? Maybe an ioctl?
Why would you want to use the kernel get_cycles()? It's trivial to
define your own function/macro based on rdtsc:
http://lxr.linux.no/source/include/asm-i386/msr.h#L41
#define rdtscll(val) \
__asm__ __volatile__ ("rdtsc" : "=A" (val))
I am actually working on an MPC5200 (Freescale PowerPC) with Denx
embedded linux distribution, and there is no rdtsc avaiable... :(
And we are getting problems with gettimeofday, because of timer
desynchronization with the time server... and jiffies can't get the
desired precision in our application.
So that's why I am trying to use get_cycles. Was it a bad idea?
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