timecounting: add getbinruntime(), getnsecruntime()

The networking people want a fast, monotonic clock that only advances
while the system is not suspended.  The runtime clock satisfies most
of these requirements, so introduce getnsecruntime() to provide a fast
means for reading it.

Based on patches from jca@ and claudio@.

ok yasuoka@

diff --git a/sys/kern/kern_tc.c b/sys/kern/kern_tc.c
index e8cc25b..16cf1fa 100644 (file)
--- a/sys/kern/kern_tc.c
+++ b/sys/kern/kern_tc.c
@@ -1,4 +1,4 @@
-/*     $OpenBSD: kern_tc.c,v 1.80 2022/12/05 23:18:37 deraadt Exp $ */
+/*     $OpenBSD: kern_tc.c,v 1.81 2022/12/13 17:30:36 cheloha Exp $ */
 
 /*
  * Copyright (c) 2000 Poul-Henning Kamp <phk@FreeBSD.org>
@@ -294,6 +294,30 @@ nanoruntime(struct timespec *ts)
        BINTIME_TO_TIMESPEC(&bt, ts);
 }
 
+void
+getbinruntime(struct bintime *bt)
+{
+       struct timehands *th;
+       u_int gen;
+
+       do {
+               th = timehands;
+               gen = th->th_generation;
+               membar_consumer();
+               bintimesub(&th->th_offset, &th->th_naptime, bt);
+               membar_consumer();
+       } while (gen == 0 || gen != th->th_generation);
+}
+
+uint64_t
+getnsecruntime(void)
+{
+       struct bintime bt;
+
+       getbinruntime(&bt);
+       return BINTIME_TO_NSEC(&bt);
+}
+
 void
 bintime(struct bintime *bt)
 {

diff --git a/sys/sys/time.h b/sys/sys/time.h
index d4736c9..20bfba4 100644 (file)
--- a/sys/sys/time.h
+++ b/sys/sys/time.h
@@ -1,4 +1,4 @@
-/*     $OpenBSD: time.h,v 1.62 2022/07/23 22:58:51 cheloha Exp $       */
+/*     $OpenBSD: time.h,v 1.63 2022/12/13 17:30:36 cheloha Exp $       */
 /*     $NetBSD: time.h,v 1.18 1996/04/23 10:29:33 mycroft Exp $        */
 
 /*
@@ -318,6 +318,9 @@ void        nanoboottime(struct timespec *);
 void   binruntime(struct bintime *);
 void   nanoruntime(struct timespec *);
 
+void getbinruntime(struct bintime *);
+uint64_t getnsecruntime(void);
+
 time_t gettime(void);
 time_t getuptime(void);