Re: Please test EARLY_AP_STARTUP

On Wed, Nov 30, 2016 at 9:59 AM, Sepherosa Ziehau <sepherosa_at_gmail.com> wrote:
> On Tue, Nov 29, 2016 at 2:27 AM, John Baldwin <jhb_at_freebsd.org> wrote:
>> On Monday, November 28, 2016 02:35:07 PM Sepherosa Ziehau wrote:
>>> Hi John,
>>>
>>> fdc seems to cause panic on Hyper-V:
>>> https://people.freebsd.org/~sephe/fdc_panic.png
>>
>> You shouldn't get this panic in latest HEAD (post-r309148).
>
>
> The base of my kernel tree is ~20 days old :)
>
>
>>
>>> I then commented out device fdc, and I fixed one panic on Hyper-V here:
>>> https://reviews.freebsd.org/D8656
>>
>> Replied to the review.
>>
>>> 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.

Thanks,
sephe

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