minix/kernel/system/do_times.c
Thomas Cort 5142b1f388 kernel: rename realtime to monotonic, add realtime
Old realtime was used for both timers (where an accurate count of
all ticks is needed) and the system time. In order to implement
adjtime(2), these duties must be separated as changing the time
of day by a small amount shouldn't affect timers in any way nor
should it change the boot time.

Following the naming of the clocks used by clock_gettime(2). The
clock named 'realtime' will represent the best guess at the
current wall clock time, and the clock named 'monotonic' will
represent the absolute time the system has been running.
Use monotonic for timers in kernel and in drivers. Use realtime
for determining time of day, dates, etc.

This commit simply renames realtime to monotonic and adds a new
tick counter named realtime. There are no functional changes in
this commit. It just lays the foundation for future work.
2013-04-04 15:04:52 +02:00

44 lines
1.3 KiB
C

/* The kernel call implemented in this file:
* m_type: SYS_TIMES
*
* The parameters for this kernel call are:
* m4_l1: T_ENDPT (get info for this process)
* m4_l1: T_USER_TIME (return values ...)
* m4_l2: T_SYSTEM_TIME
* m4_l3: T_BOOTTIME
* m4_l5: T_BOOT_TICKS
*/
#include "kernel/system.h"
#include <minix/endpoint.h>
#if USE_TIMES
/*===========================================================================*
* do_times *
*===========================================================================*/
int do_times(struct proc * caller, message * m_ptr)
{
/* Handle sys_times(). Retrieve the accounting information. */
register const struct proc *rp;
int proc_nr;
endpoint_t e_proc_nr;
/* Insert the times needed by the SYS_TIMES kernel call in the message.
* The clock's interrupt handler may run to update the user or system time
* while in this code, but that cannot do any harm.
*/
e_proc_nr = (m_ptr->T_ENDPT == SELF) ? caller->p_endpoint : m_ptr->T_ENDPT;
if(e_proc_nr != NONE && isokendpt(e_proc_nr, &proc_nr)) {
rp = proc_addr(proc_nr);
m_ptr->T_USER_TIME = rp->p_user_time;
m_ptr->T_SYSTEM_TIME = rp->p_sys_time;
}
m_ptr->T_BOOT_TICKS = get_monotonic();
m_ptr->T_BOOTTIME = boottime;
return(OK);
}
#endif /* USE_TIMES */