Date: Thu, 3 Oct 2019 09:10:16 -0600 From: Warner Losh <imp@bsdimp.com> To: Konstantin Belousov <kostikbel@gmail.com> Cc: Bruce Evans <brde@optusnet.com.au>, 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: <CANCZdfpcOBJiYAKafhiWZS2g4vnLGVvzqhaOXetSSnU2Hj91nw@mail.gmail.com> In-Reply-To: <20191003084021.GI44691@kib.kiev.ua> 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> <20191003084021.GI44691@kib.kiev.ua>
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I think this is a good fix. I recall phk saying it was more paranoia for edge cases than really needed in a private email to me, but it's in the 'gap' of email that I lost in a disk crash 12 years ago so I can't find it for sure. Warner On Thu, Oct 3, 2019 at 2:40 AM Konstantin Belousov <kostikbel@gmail.com> wrote: > 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); > _______________________________________________ > freebsd-hackers@freebsd.org mailing list > https://lists.freebsd.org/mailman/listinfo/freebsd-hackers > To unsubscribe, send any mail to "freebsd-hackers-unsubscribe@freebsd.org" >
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