On Sat, 30 Jul 2016 12:03:59 -0700 John Baldwin <j...@freebsd.org> wrote:
> On Saturday, July 30, 2016 09:44:22 AM Gary Jennejohn wrote: > > On Fri, 29 Jul 2016 13:17:42 -0700 > > John Baldwin <j...@freebsd.org> wrote: > > > > > On Thursday, July 28, 2016 12:31:31 AM Gary Jennejohn wrote: > > > > Well, now I know that ULE is a prerequiste for EARLY_AP_STARTUP! I > > > > wasn't aware of that. I prefer BSD and that's the scheduler I did > > > > the first tests with. > > > > > > > > But with the ULE scheduler the system comes up all the way. > > > > > > > > It would be nice if the BSD scheduler could also be modified to > > > > work with EARLY_AP_STARTUP. > > > > > > I wasn't able to reproduce your hang with 4BSD, but I think I see a > > > possible problem. Try this: > > > > > > diff --git a/sys/kern/sched_4bsd.c b/sys/kern/sched_4bsd.c > > > index 7de56b6..d53331a 100644 > > > --- a/sys/kern/sched_4bsd.c > > > +++ b/sys/kern/sched_4bsd.c > > > @@ -327,7 +327,6 @@ maybe_preempt(struct thread *td) > > > * - The current thread has a higher (numerically lower) or > > > * equivalent priority. Note that this prevents curthread from > > > * trying to preempt to itself. > > > - * - It is too early in the boot for context switches (cold is set). > > > * - The current thread has an inhibitor set or is in the process of > > > * exiting. In this case, the current thread is about to switch > > > * out anyways, so there's no point in preempting. If we did, > > > @@ -348,7 +347,7 @@ maybe_preempt(struct thread *td) > > > ("maybe_preempt: trying to run inhibited thread")); > > > pri = td->td_priority; > > > cpri = ctd->td_priority; > > > - if (panicstr != NULL || pri >= cpri || cold /* || dumping */ || > > > + if (panicstr != NULL || pri >= cpri /* || dumping */ || > > > TD_IS_INHIBITED(ctd)) > > > return (0); > > > #ifndef FULL_PREEMPTION > > > @@ -1127,7 +1126,7 @@ forward_wakeup(int cpunum) > > > if ((!forward_wakeup_enabled) || > > > (forward_wakeup_use_mask == 0 && forward_wakeup_use_loop == 0)) > > > return (0); > > > - if (!smp_started || cold || panicstr) > > > + if (!smp_started || panicstr) > > > return (0); > > > > > > forward_wakeups_requested++; > > > > > > > Thanks, but with this patch the kernel hangs in exactly the same > > place as before - after the HPET output. > > > > Maybe I'm missing some kernel option which ULE works around, or > > something like that. > > Hmm, ok. Please add KTR_RUNQ and KTR_SMP to the KTR masks, that is > 'options KTR_COMPILE=(KTR_PROC|KTR_RUNQ|KTR_SMP)' and > 'options KTR_MASK=(KTR_PROC|KTR_RUNQ|KTR_SMP)' > > Please also add this patch (on top of the previous patch): > > diff --git a/sys/kern/sched_4bsd.c b/sys/kern/sched_4bsd.c > index 2973a23..bab2278 100644 > --- a/sys/kern/sched_4bsd.c > +++ b/sys/kern/sched_4bsd.c > @@ -1278,6 +1278,8 @@ sched_add(struct thread *td, int flags) > KASSERT(td->td_flags & TDF_INMEM, > ("sched_add: thread swapped out")); > > + CTR2(KTR_PROC, "sched_add: thread %d (%s)", td->td_tid, > + sched_tdname(td)); > KTR_STATE2(KTR_SCHED, "thread", sched_tdname(td), "runq add", > "prio:%d", td->td_priority, KTR_ATTR_LINKED, > sched_tdname(curthread)); > diff --git a/sys/x86/x86/cpu_machdep.c b/sys/x86/x86/cpu_machdep.c > index f07b97e..1f418f1 100644 > --- a/sys/x86/x86/cpu_machdep.c > +++ b/sys/x86/x86/cpu_machdep.c > @@ -440,6 +440,7 @@ cpu_idle_wakeup(int cpu) > return (0); > if (*state == STATE_MWAIT) > *state = STATE_RUNNING; > + CTR1(KTR_PROC, "cpu_idle_wakeup: wokeup CPU %d", cpu); > return (1); > } > > (I haven't tried compiling it, you might have to add the sys/ktr.h > header to cpu_machdep.c if it doesn't build.) > > Hopefully we will get some better trace messages before it hangs > with this added info. The root issue seems to be that 4BSD is > pinning thread0 to some other CPU (due to sched_bind that happens > inside of bus_bind_intr() when the HPET driver pins IRQs to CPUs) > and that other CPU isn't waking up to realize it needs to run thread0. > It compiled with no changes needed. Even though I set MAXCPU to a mere 2, the boot still hadn't completed after 90 minutes and I broke it off. I still have the kernel, so I can try it another time when I have less need for my FreeBSD box. -- Gary Jennejohn _______________________________________________ firstname.lastname@example.org mailing list https://lists.freebsd.org/mailman/listinfo/freebsd-current To unsubscribe, send any mail to "freebsd-current-unsubscr...@freebsd.org"