Thanks!
On Mon, Sep 9, 2019 at 11:48 AM Konstantin Belousov <kostik...@gmail.com> wrote: > > On Mon, Sep 09, 2019 at 11:31:32AM -0700, Conrad Meyer wrote: > > What’s the motivation for using more timehands? > See the thread titled 'Is it a good idea to use a usb-serial adapter > for PPS input? Yes, it is.' on arm@ and usb@. In short, there are some > reports of timecounters misbehaving on single-core systems when only two > timehands are enabled. > > The change eases the experimentation and provides a workaround which does > not require modifying the sources to apply. > > > > > On Mon, Sep 9, 2019 at 04:30 Konstantin Belousov <k...@freebsd.org> wrote: > > > > > 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 <dar...@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); > > > > > > _______________________________________________ svn-src-all@freebsd.org mailing list https://lists.freebsd.org/mailman/listinfo/svn-src-all To unsubscribe, send any mail to "svn-src-all-unsubscr...@freebsd.org"