On Fri, May 17, 2013 at 2:59 PM, devendra.aaru <devendra.aaru@xxxxxxxxx> wrote:
Hello,
The Select system call has given the timeout of 100 msec and but its
expired after 115 msecs.
I have no fds to read, and just wanted to use select as the timer to
timeout and so some stuff after the timeout happen.
code:
#include <stdio.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <sys/select.h>
main()
{
int ret;
struct timeout tv;
tv.tv_sec = 0;
tv.tv_usec = 100000;
while (1) {
ret = select(5, 0, 0, 0, &tv);
if (ret == 0) {
struct timeval t;
gettimeofday(&t, 0);
printf("sec = %d-usec = %d\n", t.tv_sec, t.tv_usec);
}
}
}
my kernel is older, 2.6.23.
thanks,
As the manual page for select specifies (see below) you should expect some delays due to kernel scheduling. If you need more precision you might wanna try something else.
The timeout argument specifies the minimum interval that select() should block waiting for a file descriptor to become ready. (This interval will be rounded up to the system clock granularity, and kernel scheduling delays mean that the blocking interval may overrun by a small amount.) If both fields of the timeval structure are zero, then select() returns immediately. (This is useful for polling.) If timeout is NULL (no timeout), select() can block indefinitely.
Regards,
Victor.
_______________________________________________ Kernelnewbies mailing list Kernelnewbies@xxxxxxxxxxxxxxxxx http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
