Re: Please test EARLY_AP_STARTUP

On Thursday, December 01, 2016 01:53:29 PM Sepherosa Ziehau wrote:
> On Wed, Nov 30, 2016 at 9:59 AM, Sepherosa Ziehau <sepherosa_at_gmail.com> wrote:
> >>> After fdc is disabled and hyperv/storvsc is fixed, it seems to boot
> >>> fine, except a long delay (28~30seconds) here:
> >>> ....
> >>> Timecounters tick every 1.000 msec
> >>> -----
> >>> 28 ~ 30 seconds delay
> >>> -----
> >>> vlan: initialized, using hash tables with chaining
> >>> ....
> >>>
> >>> I have the bootverbose dmesg here:
> >>> https://people.freebsd.org/~sephe/dmesg_earlyap.txt
> >>>
> >>> I booted 10 times, only one boot does not suffer this 30 seconds
> >>> delay.  It sounds like some races to me.  Any hints?
> >>
> >> It is likely a race as we start running things sooner now, yes.  Can you
> >> break into DDB during the hang and see what thread0 is waiting on?  If
> >> it is in the interrupt hooks you can use 'show conifhk' in DDB to see the
> >> list of pending interrupt hooks.  That provides a list of candidate drivers
> >> to inspect (e.g. stack traces of relevant kthreads) for what is actually
> >> waiting (and what it is waiting on)
> >
> > Just tried, but I failed to break into DDB during the 30 seconds
> > delay.  DDB was entered after the 30 seconds delay, though I press the
> > break key when the delay started.
> 
> I tried add VERBOSE_SYSINIT option in order to get a rough location of
> this delay, but the system boots just fine w/ VERBOSE_SYSINIT option,
> sigh.

You could add KTR_PROC tracing and use 'show ktr' in DDB when you break in after the
30 second delay to see what it was doing during the delay perhaps?

-- 
John Baldwin