Calculating CPU load from kernel module...

[Cormac_Redmond]

Hi..

Basically we're making a load balancer, and we need a way of finding CPU load, somehow from inside the kernel. Using a user-space program isn't an option(too slow)...

How can I access /proc/loadavg or /proc/stat from within the kernel??
Or is there some systems calls I can use?

Any help greatly appreciated.

Cormac Redmond.

[cbogdan]

Hi,

#include <stdlib.h>
#include <stdio.h>
double loadavg[3];
main ()
{
int i;
getloadavg(loadavg, sizeof(loadavg) / sizeof(loadavg[0]));
for (i = 0; i < (sizeof(loadavg)/sizeof(loadavg[0])); i++)
printf(" %.2f\n", loadavg[i]);
}


Compare the results with this shell command:

awk '{print "1 min:\t" $1 "\n5 min:\t" $2 "\n15 min:\t" $3 }' /proc/loadavg

[tb10alj]

Hi..
Basically we're making a load balancer, and we need a way of finding CPU load, somehow from inside the kernel. Using a user-space program isn't an option(too slow)...

Have a look at loadavg_read_proc() in fs/proc/proc_misc.c
There you can see, how the values for /proc/loadavg are calculated.


regards
JAN

[Cormac_Redmond]

Thanks guys...