svn commit: r352059 - head/sys/kern
Konstantin Belousov
kib at FreeBSD.org
Mon Sep 9 11:29:59 UTC 2019
Author: kib
Date: Mon Sep 9 11:29:58 2019
New Revision: 352059
URL: https://svnweb.freebsd.org/changeset/base/352059
Log:
Make timehands count selectable at boottime.
Tested by: O'Connor, Daniel <darius at dons.net.au>
Sponsored by: The FreeBSD Foundation
MFC after: 1 week
Differential revision: https://reviews.freebsd.org/D21563
Modified:
head/sys/kern/kern_tc.c
Modified: head/sys/kern/kern_tc.c
==============================================================================
--- head/sys/kern/kern_tc.c Mon Sep 9 11:22:38 2019 (r352058)
+++ head/sys/kern/kern_tc.c Mon Sep 9 11:29:58 2019 (r352059)
@@ -83,19 +83,16 @@ struct timehands {
struct timehands *th_next;
};
-static struct timehands th0;
-static struct timehands th1 = {
- .th_next = &th0
-};
-static struct timehands th0 = {
+static struct timehands ths[16] = {
+ [0] = {
.th_counter = &dummy_timecounter,
.th_scale = (uint64_t)-1 / 1000000,
.th_offset = { .sec = 1 },
.th_generation = 1,
- .th_next = &th1
+ },
};
-static struct timehands *volatile timehands = &th0;
+static struct timehands *volatile timehands = &ths[0];
struct timecounter *timecounter = &dummy_timecounter;
static struct timecounter *timecounters = &dummy_timecounter;
@@ -115,6 +112,10 @@ static int timestepwarnings;
SYSCTL_INT(_kern_timecounter, OID_AUTO, stepwarnings, CTLFLAG_RW,
×tepwarnings, 0, "Log time steps");
+static int timehands_count = 2;
+SYSCTL_INT(_kern_timecounter, OID_AUTO, timehands_count, CTLFLAG_RDTUN,
+ &timehands_count, 0, "Count of timehands in rotation");
+
struct bintime bt_timethreshold;
struct bintime bt_tickthreshold;
sbintime_t sbt_timethreshold;
@@ -1960,8 +1961,9 @@ done:
static void
inittimecounter(void *dummy)
{
+ struct timehands *thp;
u_int p;
- int tick_rate;
+ int i, tick_rate;
/*
* Set the initial timeout to
@@ -1987,6 +1989,16 @@ inittimecounter(void *dummy)
#ifdef FFCLOCK
ffclock_init();
#endif
+
+ /* Set up the requested number of timehands. */
+ if (timehands_count < 1)
+ timehands_count = 1;
+ if (timehands_count > nitems(ths))
+ timehands_count = nitems(ths);
+ for (i = 1, thp = &ths[0]; i < timehands_count; thp = &ths[i++])
+ thp->th_next = &ths[i];
+ thp->th_next = &ths[0];
+
/* warm up new timecounter (again) and get rolling. */
(void)timecounter->tc_get_timecount(timecounter);
(void)timecounter->tc_get_timecount(timecounter);
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