92 lines
1.9 KiB
C
92 lines
1.9 KiB
C
/* getidle.c - by David van Moolenbroek <dcvmoole@cs.vu.nl> */
|
|
|
|
/* Usage:
|
|
*
|
|
* double idleperc;
|
|
* getidle();
|
|
* ...
|
|
* idleperc = getidle();
|
|
* printf("CPU usage: %lg%%\n", 100.0 - idleperc);
|
|
*
|
|
* This routine goes through PM to get the idle time, rather than making the
|
|
* sys_getinfo() call to the kernel directly. This means that it can be used
|
|
* by non-system processes as well, but it will incur some extra overhead in
|
|
* the system case. The overhead does not end up being measured, because the
|
|
* system is clearly not idle while the system calls are being made. In any
|
|
* case, for this reason, only one getidle() run is allowed at a time.
|
|
*
|
|
* Note that the kernel has to be compiled with CONFIG_IDLE_TSC support.
|
|
*/
|
|
|
|
#define _MINIX 1
|
|
#define _SYSTEM 1
|
|
#include <minix/sysinfo.h>
|
|
#include <minix/u64.h>
|
|
#include <minix/sysutil.h>
|
|
|
|
static u64_t start, idle;
|
|
static int running = 0;
|
|
|
|
static double make_double(u64_t d)
|
|
{
|
|
/* Convert a 64-bit fixed point value into a double.
|
|
* This whole thing should be replaced by something better eventually.
|
|
*/
|
|
double value;
|
|
size_t i;
|
|
|
|
value = (double) ex64hi(d);
|
|
for (i = 0; i < sizeof(unsigned long); i += 2)
|
|
value *= 65536.0;
|
|
|
|
value += (double) ex64lo(d);
|
|
|
|
return value;
|
|
}
|
|
|
|
double getidle(void)
|
|
{
|
|
u64_t stop, idle2;
|
|
u64_t idelta, tdelta;
|
|
double ifp, tfp, rfp;
|
|
int r;
|
|
|
|
if (!running) {
|
|
r = getsysinfo_up(PM_PROC_NR, SIU_IDLETSC, sizeof(idle), &idle);
|
|
if (r != sizeof(idle))
|
|
return -1.0;
|
|
|
|
running = 1;
|
|
|
|
read_tsc_64(&start);
|
|
|
|
return 0.0;
|
|
}
|
|
else {
|
|
read_tsc_64(&stop);
|
|
|
|
running = 0;
|
|
|
|
r = getsysinfo_up(PM_PROC_NR, SIU_IDLETSC, sizeof(idle2), &idle2);
|
|
if (r != sizeof(idle2))
|
|
return -1.0;
|
|
|
|
idelta = sub64(idle2, idle);
|
|
tdelta = sub64(stop, start);
|
|
|
|
if (cmp64(idelta, tdelta) >= 0)
|
|
return 100.0;
|
|
|
|
ifp = make_double(idelta);
|
|
tfp = make_double(tdelta);
|
|
|
|
rfp = ifp / tfp * 100.0;
|
|
|
|
if (rfp < 0.0) rfp = 0.0;
|
|
else if (rfp > 100.0) rfp = 100.0;
|
|
|
|
return rfp;
|
|
}
|
|
|
|
running = !running;
|
|
}
|