lkml.org 
[lkml]   [2004]   [Jul]   [14]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
Date
From
SubjectRe: gettimeofday nanoseconds patch (makes it possible for the posix-timer functions to return higher accuracy)
On Wed, 14 Jul 2004, Matthew Wilcox wrote:
> You seem to have included two patches here that are very similar ...
> could you send the patch you intended please?

Right. Somehow my patch management system did something strange.
Here is the patch:

Index: linux-2.6.7/kernel/time.c
===================================================================
--- linux-2.6.7.orig/kernel/time.c
+++ linux-2.6.7/kernel/time.c
@@ -421,6 +421,41 @@

EXPORT_SYMBOL(current_kernel_time);

+#ifdef CONFIG_TIME_INTERPOLATION
+void gettimeofday (struct timespec *tv)
+{
+ unsigned long seq,sec,nsec;
+
+ do {
+ seq = read_seqbegin(&xtime_lock);
+ sec = xtime.tv_sec;
+ nsec = xtime.tv_nsec+time_interpolator_get_offset();
+ } while (unlikely(read_seqretry(&xtime_lock, seq)));
+
+ while (unlikely(nsec >= NSEC_PER_SEC)) {
+ nsec -= NSEC_PER_SEC;
+ ++sec;
+ }
+ tv->tv_sec = sec;
+ tv->tv_nsec = nsec;
+}
+#else
+/*
+ * Simulate gettimeofday using do_gettimeofday which only allows a timeval
+ * and therefore only yields usec accuracy
+ */
+void gettimeofday(struct timespec *tv)
+{
+ struct timeval x;
+
+ do_gettimeofday(&x);
+ tv->tv_sec = x.tv_sec;
+ tv->tv_nsec = x.tv_usec*NSEC_PER_USEC;
+}
+#endif
+
+EXPORT_SYMBOL(gettimeofday);
+
#if (BITS_PER_LONG < 64)
u64 get_jiffies_64(void)
{
Index: linux-2.6.7/kernel/timer.c
===================================================================
--- linux-2.6.7.orig/kernel/timer.c
+++ linux-2.6.7/kernel/timer.c
@@ -1241,8 +1241,7 @@
* too.
*/

- do_gettimeofday((struct timeval *)&tp);
- tp.tv_nsec *= NSEC_PER_USEC;
+ gettimeofday(&tp);
tp.tv_sec += wall_to_monotonic.tv_sec;
tp.tv_nsec += wall_to_monotonic.tv_nsec;
if (tp.tv_nsec - NSEC_PER_SEC >= 0) {
Index: linux-2.6.7/kernel/posix-timers.c
===================================================================
--- linux-2.6.7.orig/kernel/posix-timers.c
+++ linux-2.6.7/kernel/posix-timers.c
@@ -1168,15 +1168,10 @@
*/
static int do_posix_gettime(struct k_clock *clock, struct timespec *tp)
{
- struct timeval tv;
-
if (clock->clock_get)
return clock->clock_get(tp);

- do_gettimeofday(&tv);
- tp->tv_sec = tv.tv_sec;
- tp->tv_nsec = tv.tv_usec * NSEC_PER_USEC;
-
+ gettimeofday(tp);
return 0;
}

@@ -1192,24 +1187,16 @@
struct timespec *tp, struct timespec *mo)
{
u64 jiff;
- struct timeval tpv;
unsigned int seq;

do {
seq = read_seqbegin(&xtime_lock);
- do_gettimeofday(&tpv);
+ gettimeofday(tp);
*mo = wall_to_monotonic;
jiff = jiffies_64;

} while(read_seqretry(&xtime_lock, seq));

- /*
- * Love to get this before it is converted to usec.
- * It would save a div AND a mpy.
- */
- tp->tv_sec = tpv.tv_sec;
- tp->tv_nsec = tpv.tv_usec * NSEC_PER_USEC;
-
return jiff;
}

Index: linux-2.6.7/include/linux/time.h
===================================================================
--- linux-2.6.7.orig/include/linux/time.h
+++ linux-2.6.7/include/linux/time.h
@@ -348,6 +348,7 @@
struct itimerval;
extern int do_setitimer(int which, struct itimerval *value, struct itimerval *ovalue);
extern int do_getitimer(int which, struct itimerval *value);
+extern void gettimeofday (struct timespec *tv);

static inline void
set_normalized_timespec (struct timespec *ts, time_t sec, long nsec)
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
\
 
 \ /
  Last update: 2005-03-22 14:04    [W:0.262 / U:0.764 seconds]
©2003-2014 Jasper Spaans. Advertise on this site