mlx4en, timer irq @100%...

[Ben RUBSON]

> On 04 Aug 2017, at 19:45, Hans Petter Selasky <hps at selasky.org> wrote:
> 
> On 08/04/17 19:42, Ben RUBSON wrote:
>>> On 04 Aug 2017, at 19:31, Hans Petter Selasky <hps at selasky.org> wrote:
>>> 
>>> On 08/04/17 19:13, Ben RUBSON wrote:
>>>>    12 100029 intr             swi4: clock (0)  tcp_tw_2msl_scan pfslowtimo softclock_call_cc softclock intr_event_execute_handlers ithread_loop fork_exit fork_trampoline
>>> 
>>> Hi,
>>> 
>>> Can you "procstat -ak" a few times and grep for swi4. If the entry above does not disappear this is the culpit. Either the callout list is corrupted or there is an issue inside tcp_tw_2msl_scan().
>> Still here since my log catch 30 minutes ago, and sounds like it does not want to disappear.
>>> I'm CC'ing Glebius hence he's been involved with timer issues in the kernel earlier.
>> Feel free to ask me whatever you need to investigate on this !
>> I let this (production :/) server in this state to have a chance to get interesting traces.
> 
> Hi,
> 
> I guess we need to involve kgdb to get the full backtrace. Let's wait and see if anyone here knows how to do it right so the machine doesn't crash and the state is lost.

I used to test kernel dump with "sysctl debug.kdb.panic=1" and it worked correctly.
However I'm not sure about debug.minidump, if we can have it enabled or if it should be set to 0 in our case.
Let's wait for others to be sure yes.

Ben