DosPerfSysCall
Retrieve system performance information.
Syntax
DosPerfSysCall(ulCommand, ulParm1, ulParm2, ulParm3);
Parameters
- ulCommand (ULONG) - input
- Command
- DosPerfSysCall accepts the following command:
- CMD_KI_RDCNT (0x63): Read CPU utilization information in both uniprocessor and symmetric multi-processor (SMP) environments by taking a snapshot of the time stamp counters. To determine CPU utilization, the application must compute the difference between two time stamp snapshots using 64-bit arithmetic. See the example code for details.
- ulParm1 (ULONG) - in/out
- Command specific parameter 1
- Parameter usage depends on the command specified:
- CMD_KI_RDCNT : Pointer to an array of CPUUTIL structures, with one entry for each processor. On a 4-way SMP machine, the array definition would be:
CPUUTIL CPUUtil[4]; /* For processor IDs 0, 1, 2, and 3 */
- since processor numbers and arrays are both 0-based. ulParm1 would be set to the address of CPUUtil[0].
ulParm2 and ulParm3 are not used and should be set to zero.
- ulParm2 (ULONG) - in/out
- Command specific parameter 2
- Parameter usage depends on the command specified:
- CMD_KI_RDCNT 0 (reserved)
- ulParm3 (ULONG) - in/out
- Command specific parameter 3
- Parameter usage depends on the command specified:
- CMD_KI_RDCNT 0 (reserved)
Return Code
- ulrc (APIRET) - returns
- DosPerfSysCall returns one of the following values:
- 0 NO_ERROR
- 1 ERROR_INVALID_FUNCTION
Remarks
DosPerfSysCall is a general purpose performance function. This function accepts four parameters. The first parameter is the command requested. The other three parameters are command specific. DosPerfSysCall is intended to be extended by IBM in the future for other performance related functions.
Some functions of DosPerfSysCall may have a dependency on Intel Pentium or Pentium-Pro support. If a function cannot be provided because OS/2 is not running on an processor with the required features, a return code will indicate an attempt to use an unsupported function.
The perfutil.h file referenced in the example code may or may not be shipped as part of the Toolkit. In the event that it is not, its contents are:
#ifdef __cplusplus
extern "C" {
#endif
#ifndef PERFCALL_INCLUDED
#define PERFCALL_INCLUDED
/*
DosPerfSysCall Function Prototype
*/
/* The ordinal for DosPerfSysCall (in BSEORD.H) */
/* is defined as ORD_DOS32PERFSYSCALL */
APIRET APIENTRY DosPerfSysCall(ULONG ulCommand, ULONG ulParm1, ULONG ulParm2, ULONG ulParm3);
/***
*
* CPU Utilization
* ---------------
*
**/
#define CMD_KI_RDCNT (0x63)
typedef struct _CPUUTIL {
ULONG ulTimeLow; /* Low 32 bits of time stamp */
ULONG ulTimeHigh; /* High 32 bits of time stamp */
ULONG ulIdleLow; /* Low 32 bits of idle time */
ULONG ulIdleHigh; /* High 32 bits of idle time */
ULONG ulBusyLow; /* Low 32 bits of busy time */
ULONG ulBusyHigh; /* High 32 bits of busy time */
ULONG ulIntrLow; /* Low 32 bits of interrupt time */
ULONG ulIntrHigh; /* High 32 bits of interrupt time */
} CPUUTIL;
typedef CPUUTIL *PCPUUTIL;
#ifdef __cplusplus
}
#endif
It may also be necessary to define the ordinal for this function:
#define ORD_DOS32PERFSYSCALL 976
Example Code
This example uses DosPerfSysCall to obtain CPU Utilization information on a uniprocessor.
#define INCL_BASE
#include <os2.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <perfutil.h>
/*
Convert 8-byte (low, high) time value to double
*/
#define LL2F(high, low) (4294967296.0*(high)+(low))
/* This is a 1 processor example */
void main (int argc, char *argv[])
{
APIRET rc;
int i, iter, sleep_sec;
double ts_val, ts_val_prev;
double idle_val, idle_val_prev;
double busy_val, busy_val_prev;
double intr_val, intr_val_prev;
CPUUTIL CPUUtil;
if ((argc < 2) || (*argv[1] < '1') || (*argv[1] > '9')) {
fprintf(stderr, "usage: %s [1-9]\n", argv[0]);
exit(0);
}
sleep_sec = *argv[1] - '0';
iter = 0;
do {
rc = DosPerfSysCall(CMD_KI_RDCNT,(ULONG) &CPUUtil,0,0);
if (rc) {
fprintf(stderr, "CMD_KI_RDCNT failed rc = %d\n",rc);
exit(1);
}
ts_val = LL2F(CPUUtil.ulTimeHigh, CPUUtil.ulTimeLow);
idle_val = LL2F(CPUUtil.ulIdleHigh, CPUUtil.ulIdleLow);
busy_val = LL2F(CPUUtil.ulBusyHigh, CPUUtil.ulBusyLow);
intr_val = LL2F(CPUUtil.ulIntrHigh, CPUUtil.ulIntrLow);
if (iter > 0) {
double ts_delta = ts_val - ts_val_prev;
printf("idle: %4.2f%% busy: %4.2f%% intr: %4.2f%%\n",
(idle_val - idle_val_prev)/ts_delta*100.0,
(busy_val - busy_val_prev)/ts_delta*100.0,
(intr_val - intr_val_prev)/ts_delta*100.0);
}
ts_val_prev = ts_val;
idle_val_prev = idle_val;
busy_val_prev = busy_val;
intr_val_prev = intr_val;
iter++;
DosSleep(1000*sleep_sec);
} while (1);
}
