From 37da5e53c6280f05d4f07eae5490b98fa920f898 Mon Sep 17 00:00:00 2001 From: Konstantin Belousov Date: Mon, 16 Sep 2019 06:15:22 +0000 Subject: [PATCH] MFC r352059, r352060: Make timehands count selectable at boottime. --- sys/kern/kern_tc.c | 36 +++++++++++++++++++++++++++++------- 1 file changed, 29 insertions(+), 7 deletions(-) diff --git a/sys/kern/kern_tc.c b/sys/kern/kern_tc.c index e55290df785..69922abef90 100644 --- a/sys/kern/kern_tc.c +++ b/sys/kern/kern_tc.c @@ -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 +112,11 @@ 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 | CTLFLAG_NOFETCH, + &timehands_count, 0, "Count of timehands in rotation"); + struct bintime bt_timethreshold; struct bintime bt_tickthreshold; sbintime_t sbt_timethreshold; @@ -1956,6 +1958,25 @@ sysctl_kern_timecounter_adjprecision(SYSCTL_HANDLER_ARGS) return (0); } +/* Set up the requested number of timehands. */ +static void +inittimehands(void *dummy) +{ + struct timehands *thp; + int i; + + TUNABLE_INT_FETCH("kern.timecounter.timehands_count", + &timehands_count); + 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]; +} +SYSINIT(timehands, SI_SUB_TUNABLES, SI_ORDER_ANY, inittimehands, NULL); + static void inittimecounter(void *dummy) { @@ -1986,6 +2007,7 @@ inittimecounter(void *dummy) #ifdef FFCLOCK ffclock_init(); #endif + /* warm up new timecounter (again) and get rolling. */ (void)timecounter->tc_get_timecount(timecounter); (void)timecounter->tc_get_timecount(timecounter); -- 2.45.0