Attachment 232127 Details for Bug 262215 – patch for 10.4 - 14-CURRENT

[patch] patch for 10.4 - 14-CURRENT

12.3-cputime-precision.patch (text/plain), 1.96 KB, created by firk on 2022-02-26 23:11:31 UTC

(hide)

Description:

Filename:

MIME Type:

Creator: firk

Created: 2022-02-26 23:11:31 UTC

Size: 1.96 KB

patch

obsolete

>diff -ur 12.3-releng/sys/kern/kern_tc.c 12.3-my/sys/kern/kern_tc.c
>--- 12.3-releng/sys/kern/kern_tc.c	2022-02-13 15:26:52.000000000 +0300
>+++ 12.3-my/sys/kern/kern_tc.c	2022-02-27 00:38:49.000000000 +0300
>@@ -2094,20 +2094,18 @@
>  * years) and in 64 bits at 4 GHz (146 years), but if we do a multiply
>  * before divide conversion (to retain precision) we find that the
>  * margin shrinks to 1.5 hours (one millionth of 146y).
>- * With a three prong approach we never lose significant bits, no
>- * matter what the cputick rate and length of timeinterval is.
>  */
> 
> uint64_t
> cputick2usec(uint64_t tick)
> {
>-
>-	if (tick > 18446744073709551LL)		/* floor(2^64 / 1000) */
>-		return (tick / (cpu_tickrate() / 1000000LL));
>-	else if (tick > 18446744073709LL)	/* floor(2^64 / 1000000) */
>-		return ((tick * 1000LL) / (cpu_tickrate() / 1000LL));
>+	uint64_t tr;
>+	tr = cpu_tickrate();
>+	if (tick <= 18446744073709LL)
>+		return ((tick * 1000000ULL) / tr);
> 	else
>-		return ((tick * 1000000LL) / cpu_tickrate());
>+		return ((tick / tr) * 1000000ULL) +
>+		    ((tick % tr) * 1000000ULL) / tr;
> }
> 
> cpu_tick_f	*cpu_ticks = tc_cpu_ticks;
>diff -ur 12.3-releng/sys/kern/kern_time.c 12.3-my/sys/kern/kern_time.c
>--- 12.3-releng/sys/kern/kern_time.c	2022-02-13 15:26:53.000000000 +0300
>+++ 12.3-my/sys/kern/kern_time.c	2022-02-27 00:25:26.000000000 +0300
>@@ -243,9 +243,10 @@
> static inline void
> cputick2timespec(uint64_t runtime, struct timespec *ats)
> {
>-	runtime = cputick2usec(runtime);
>-	ats->tv_sec = runtime / 1000000;
>-	ats->tv_nsec = runtime % 1000000 * 1000;
>+	uint64_t tr;
>+	tr = cpu_tickrate();
>+	ats->tv_sec = runtime / tr;
>+	ats->tv_nsec = ((runtime % tr) * 1000000000ULL) / tr;
> }
> 
> void
>@@ -474,10 +475,7 @@
> 	case CLOCK_THREAD_CPUTIME_ID:
> 	case CLOCK_PROCESS_CPUTIME_ID:
> 	cputime:
>-		/* sync with cputick2usec */
>-		ts->tv_nsec = 1000000 / cpu_tickrate();
>-		if (ts->tv_nsec == 0)
>-			ts->tv_nsec = 1000;
>+		ts->tv_nsec = 1000000000 / cpu_tickrate() + 1;
> 		break;
> 	default:
> 		if ((int)clock_id < 0)

Actions: View | Diff

Attachments on bug 262215: 232127 | 232178