Hello everyone,
I have a simple code for testing QNX 6.2.1 which was installed in my system recently.
Here is source code:
[i]#include <process.h>
#include <unistd.h>
#include <time.h>
#include <sys/syspage.h>
main()
{
double dt,dt_max,dt_min;
double tic,i,j;
uint64_t t1,t2,t3,cps;
pid_t pid1;
useconds_t usec;
timespec rqtp;
int nret,schedule;
sched_param sp;
cps = SYSPAGE_ENTRY(qtime)->cycles_per_sec;
tic = 1.0/cps; // about 1.2 ns
pid1 = getpid();
printf( "I'm process %d\n", pid1 );
setprio(pid1,63);
sched_getparam(pid1,&sp);
sp.sched_priority = 63;
sched_setscheduler(pid1,SCHED_FIFO,&sp); // FIFO reduces jitter
schedule = sched_getscheduler(pid1);
t3 = ClockCycles();
dt_max = 0.0;
dt_min = 1.0e6;
for(i=0;i<1000;i++) {
t1 = ClockCycles();
// we can have 8300 loops (~420us) before jitter gets big
// for round robin scheduling
// for FIFO scheduling it is about 11000 (550us)
// probably has something to do with time slices
// or starvation protection mechanism
for(j=0;j<10000;j++) ClockCycles();
// argument is an unsigned integer value in seconds
// nanosleep is more useful
// sleep(1);
// arugment is an unsigned integer in micro seconds
// 2000 us seems to be the minimum
// not so accurate compared to nanosleep
// usleep(4000);
t2 = ClockCycles();
dt = (double)(t2-t1 )*tic / 1.0e-6; // in usec
// 2000us seems to be about the default minimum
// probably depends on the set resolution of the timer
// zero nsec results in around 1000 us delay
nsec2timespec( &rqtp, 0 );
nret = nanosleep(&rqtp,NULL);
if(dt > dt_max) dt_max = dt;
if(dt < dt_min) dt_min = dt;
}
printf("\ndt_max = %lf , dt_min = %lf",dt_max,dt_min);
printf("\nschedule = %d, %d",schedule,(int)SCHED_FIFO);
printf("\ndone.\n");
}[/i]
When I compile it, there are some errors. My file test1.c locates in folder /usr.
# gcc -I/usr/include test1.c
test1.c: In function main': test1.c:9: uint64_t’ undeclared (first use in this function)
test1.c:9: (Each undeclared identifier is reported only once
test1.c:9: for each function it appears in.)
test1.c:9: parse error before t1' test1.c:12: timespec’ undeclared (first use in this function)
test1.c:12: parse error before rqtp' test1.c:14: sched_param’ undeclared (first use in this function)
test1.c:14: parse error before sp' test1.c:16: cps’ undeclared (first use in this function)
test1.c:24: sp' undeclared (first use in this function) test1.c:26: SCHED_FIFO’ undeclared (first use in this function)
test1.c:29: t3' undeclared (first use in this function) test1.c:33: t1’ undeclared (first use in this function)
test1.c:48: t2' undeclared (first use in this function) test1.c:53: rqtp’ undeclared (first use in this function)
what’s wrong here?
Any answer is welcome.