Date: Thu, 3 Oct 2019 11:40:21 +0300 From: Konstantin Belousov <kostikbel@gmail.com> To: Bruce Evans <brde@optusnet.com.au> Cc: Sebastian Huber <sebastian.huber@embedded-brains.de>, FreeBSD <freebsd-hackers@freebsd.org> Subject: Re: Why is tc_get_timecount() called two times in tc_init()? Message-ID: <20191003084021.GI44691@kib.kiev.ua> In-Reply-To: <20191003030837.C2787@besplex.bde.org> References: <0e27fb3e-0f60-68e1-dbba-f17c3d91c332@embedded-brains.de> <20191002140040.GA44691@kib.kiev.ua> <20191003013314.O2151@besplex.bde.org> <20191002163946.GE44691@kib.kiev.ua> <20191003030837.C2787@besplex.bde.org>
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On Thu, Oct 03, 2019 at 03:12:26AM +1000, Bruce Evans wrote:
> On Wed, 2 Oct 2019, Konstantin Belousov wrote:
>
> > On Thu, Oct 03, 2019 at 02:25:46AM +1000, Bruce Evans wrote:
> >> On Wed, 2 Oct 2019, Konstantin Belousov wrote:
> > So the conclusion is that the second call can be removed, am I right ?
>
> Yes.
>
> All tc_get_timecount() functions should be checked for doing sufficient
> initialization in one call (so that deltas for subsequent calls are
> correct).
This should be it.
But, is even a single call to tc_get_timecount() needed for "warmup" ?
diff --git a/sys/dev/acpica/acpi.c b/sys/dev/acpica/acpi.c
index 382d139617d..28d0d738a58 100644
--- a/sys/dev/acpica/acpi.c
+++ b/sys/dev/acpica/acpi.c
@@ -3191,7 +3191,6 @@ acpi_resync_clock(struct acpi_softc *sc)
* Warm up timecounter again and reset system clock.
*/
(void)timecounter->tc_get_timecount(timecounter);
- (void)timecounter->tc_get_timecount(timecounter);
inittodr(time_second + sc->acpi_sleep_delay);
}
diff --git a/sys/dev/acpica/acpi_timer.c b/sys/dev/acpica/acpi_timer.c
index 34a832089a2..d768397a785 100644
--- a/sys/dev/acpica/acpi_timer.c
+++ b/sys/dev/acpica/acpi_timer.c
@@ -274,7 +274,6 @@ acpi_timer_resume_handler(struct timecounter *newtc)
"restoring timecounter, %s -> %s\n",
tc->tc_name, newtc->tc_name);
(void)newtc->tc_get_timecount(newtc);
- (void)newtc->tc_get_timecount(newtc);
timecounter = newtc;
}
}
diff --git a/sys/dev/xen/control/control.c b/sys/dev/xen/control/control.c
index 98ab5bf3a6b..1e132f4d866 100644
--- a/sys/dev/xen/control/control.c
+++ b/sys/dev/xen/control/control.c
@@ -303,7 +303,6 @@ xctrl_suspend()
* Warm up timecounter again and reset system clock.
*/
timecounter->tc_get_timecount(timecounter);
- timecounter->tc_get_timecount(timecounter);
inittodr(time_second);
#ifdef EARLY_AP_STARTUP
diff --git a/sys/kern/kern_tc.c b/sys/kern/kern_tc.c
index 9920a9a9304..847fbbbf35d 100644
--- a/sys/kern/kern_tc.c
+++ b/sys/kern/kern_tc.c
@@ -1257,7 +1257,6 @@ tc_init(struct timecounter *tc)
tc->tc_frequency < timecounter->tc_frequency)
return;
(void)tc->tc_get_timecount(tc);
- (void)tc->tc_get_timecount(tc);
timecounter = tc;
}
@@ -1519,7 +1518,6 @@ sysctl_kern_timecounter_hardware(SYSCTL_HANDLER_ARGS)
/* Warm up new timecounter. */
(void)newtc->tc_get_timecount(newtc);
- (void)newtc->tc_get_timecount(newtc);
timecounter = newtc;
@@ -2011,7 +2009,6 @@ inittimecounter(void *dummy)
/* warm up new timecounter (again) and get rolling. */
(void)timecounter->tc_get_timecount(timecounter);
- (void)timecounter->tc_get_timecount(timecounter);
mtx_lock_spin(&tc_setclock_mtx);
tc_windup(NULL);
mtx_unlock_spin(&tc_setclock_mtx);
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