Author: kib
Date: Fri Dec 16 23:42:49 2016
New Revision: 310183
URL: https://svnweb.freebsd.org/changeset/base/310183
Log:
MFC r296775 (by gibbs):
Provide high precision conversion from ns,us,ms -> sbintime in kevent.
Tested by: ian
Modified:
stable/10/sys/kern/kern_event.c
Directory Properties:
stable/10/ (props changed)
Modified: stable/10/sys/kern/kern_event.c
==============================================================================
--- stable/10/sys/kern/kern_event.c Fri Dec 16 23:33:37 2016
(r310182)
+++ stable/10/sys/kern/kern_event.c Fri Dec 16 23:42:49 2016
(r310183)
@@ -556,34 +556,59 @@ knote_fork(struct knlist *list, int pid)
#define NOTE_TIMER_PRECMASK (NOTE_SECONDS|NOTE_MSECONDS|NOTE_USECONDS| \
NOTE_NSECONDS)
-static __inline sbintime_t
+static sbintime_t
timer2sbintime(intptr_t data, int flags)
{
- sbintime_t modifier;
+ /*
+ * Macros for converting to the fractional second portion of an
+ * sbintime_t using 64bit multiplication to improve precision.
+ */
+#define NS_TO_SBT(ns) (((ns) * (((uint64_t)1 << 63) / 500000000)) >> 32)
+#define US_TO_SBT(us) (((us) * (((uint64_t)1 << 63) / 500000)) >> 32)
+#define MS_TO_SBT(ms) (((ms) * (((uint64_t)1 << 63) / 500)) >> 32)
switch (flags & NOTE_TIMER_PRECMASK) {
case NOTE_SECONDS:
- modifier = SBT_1S;
- break;
+#ifdef __LP64__
+ if (data > (SBT_MAX / SBT_1S))
+ return SBT_MAX;
+#endif
+ return ((sbintime_t)data << 32);
case NOTE_MSECONDS: /* FALLTHROUGH */
case 0:
- modifier = SBT_1MS;
- break;
+ if (data >= 1000) {
+ int64_t secs = data / 1000;
+#ifdef __LP64__
+ if (secs > (SBT_MAX / SBT_1S))
+ return SBT_MAX;
+#endif
+ return (secs << 32 | MS_TO_SBT(data % 1000));
+ }
+ return MS_TO_SBT(data);
case NOTE_USECONDS:
- modifier = SBT_1US;
- break;
+ if (data >= 1000000) {
+ int64_t secs = data / 1000000;
+#ifdef __LP64__
+ if (secs > (SBT_MAX / SBT_1S))
+ return SBT_MAX;
+#endif
+ return (secs << 32 | US_TO_SBT(data % 1000000));
+ }
+ return US_TO_SBT(data);
case NOTE_NSECONDS:
- modifier = SBT_1NS;
- break;
- default:
- return (-1);
- }
-
+ if (data >= 1000000000) {
+ int64_t secs = data / 1000000000;
#ifdef __LP64__
- if (data > SBT_MAX / modifier)
- return (SBT_MAX);
+ if (secs > (SBT_MAX / SBT_1S))
+ return SBT_MAX;
#endif
- return (modifier * data);
+ return (secs << 32 | US_TO_SBT(data % 1000000000));
+ }
+ return NS_TO_SBT(data);
+ default:
+ break;
+ }
+ return (-1);
}
static void
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