Re: Recent upgrade of 4.13 -> 4.14 issue

[Frédéric Pierret <frederic.pierret@xxxxxxxxxxxx>]

Le 10/27/20 à 10:22 AM, Dario Faggioli a écrit :
> On Tue, 2020-10-27 at 06:58 +0100, Jürgen Groß wrote:
> > On 26.10.20 17:31, Dario Faggioli wrote:
> > > Or did you have something completely different in mind, and I'm
> > > missing
> > > it?
> > No, I think you are right. I mixed that up with __context_switch()
> > not
> > being called.
> Right.
>
> > Sorry for the noise,
> Sure, no problem.
>
> In fact, this issue is apparently scheduler independent. It indeed
> seemd to be related to the other report we have "BUG: credit=sched2
> machine hang when using DRAKVUF", but there it looks like it is
> scheduler-dependant.
>
> Might it be something that lies somewhere else, but Credit2 is
> triggering it faster/easier? (Just thinking out loud...)
>
> For Frederic, what happens is that dom0 hangs, right? So you're able to
> poke at Xen with some debugkeys (like 'r' for the scheduler's status,
> and the ones for the domain's vCPUs)?
>
> If yes, it may be useful to see the output.
>
> Regards
I'm having some new info with respect to your request. Yes dom0 hangs and I can 
interact with serial console. I've succeeded to obtain the output of 'r' 
debug-keys:

```
(XEN) sched_smt_power_savings: disabled
(XEN) NOW=72810702614697
(XEN) Online Cpus: 0-15
(XEN) Cpupool 0:
(XEN) Cpus: 0-15
(XEN) Scheduling granularity: cpu, 1 CPU per sched-resource
(XEN) Scheduler: SMP Credit Scheduler (credit)
(XEN) info:
(XEN)   ncpus              = 16
(XEN)   master             = 0
(XEN)   credit             = 4800
(XEN)   credit balance     = 608
(XEN)   weight             = 12256
(XEN)   runq_sort          = 996335
(XEN)   default-weight     = 256
(XEN)   tslice             = 30ms
(XEN)   ratelimit          = 1000us
(XEN)   credits per msec   = 10
(XEN)   ticks per tslice   = 3
(XEN)   migration delay    = 0us
(XEN) idlers: 00000000,00003c99
(XEN) active units:
(XEN)     1: [0.1] pri=-1 flags=0 cpu=6 credit=214 [w=2000,cap=0]
(XEN)     2: [0.4] pri=-1 flags=0 cpu=8 credit=115 [w=2000,cap=0]
(XEN)     3: [0.5] pri=-1 flags=0 cpu=5 credit=239 [w=2000,cap=0]
(XEN)     4: [0.11] pri=-1 flags=0 cpu=1 credit=-55 [w=2000,cap=0]
(XEN)     5: [0.6] pri=-2 flags=0 cpu=15 credit=-177 [w=2000,cap=0]
(XEN)     6: [0.7] pri=-1 flags=0 cpu=2 credit=50 [w=2000,cap=0]
(XEN)     7: [19.1] pri=-2 flags=0 cpu=9 credit=-241 [w=256,cap=0]
(XEN) CPUs info:
(XEN) CPU[00] current=d[IDLE]v0, curr=d[IDLE]v0, prev=NULL
(XEN) CPU[00] nr_run=0, sort=996334, sibling={0}, core={0-7}
(XEN) CPU[01] current=d0v11, curr=d0v11, prev=NULL
(XEN) CPU[01] nr_run=1, sort=996335, sibling={1}, core={0-7}
(XEN)   run: [0.11] pri=-1 flags=0 cpu=1 credit=-55 [w=2000,cap=0]
(XEN)     1: [32767.1] pri=-64 flags=0 cpu=1
(XEN) CPU[02] current=d0v7, curr=d0v7, prev=NULL
(XEN) CPU[02] nr_run=1, sort=996335, sibling={2}, core={0-7}
(XEN)   run: [0.7] pri=-1 flags=0 cpu=2 credit=50 [w=2000,cap=0]
(XEN)     1: [32767.2] pri=-64 flags=0 cpu=2
(XEN) CPU[03] current=d[IDLE]v3, curr=d[IDLE]v3, prev=NULL
(XEN) CPU[03] nr_run=0, sort=996329, sibling={3}, core={0-7}
(XEN) CPU[04] current=d[IDLE]v4, curr=d[IDLE]v4, prev=NULL
(XEN) CPU[04] nr_run=0, sort=996325, sibling={4}, core={0-7}
(XEN) CPU[05] current=d0v5, curr=d0v5, prev=NULL
(XEN) CPU[05] nr_run=1, sort=996334, sibling={5}, core={0-7}
(XEN)   run: [0.5] pri=-1 flags=0 cpu=5 credit=239 [w=2000,cap=0]
(XEN)     1: [32767.5] pri=-64 flags=0 cpu=5
(XEN) CPU[06] current=d0v1, curr=d0v1, prev=NULL
(XEN) CPU[06] nr_run=1, sort=996334, sibling={6}, core={0-7}
(XEN)   run: [0.1] pri=-1 flags=0 cpu=6 credit=214 [w=2000,cap=0]
(XEN)     1: [32767.6] pri=-64 flags=0 cpu=6
(XEN) CPU[07] current=d[IDLE]v7, curr=d[IDLE]v7, prev=NULL
(XEN) CPU[07] nr_run=0, sort=996303, sibling={7}, core={0-7}
(XEN) CPU[08] current=d[IDLE]v8, curr=d[IDLE]v8, prev=NULL
(XEN) CPU[08] nr_run=2, sort=996335, sibling={8}, core={8-15}
(XEN)     1: [0.4] pri=-1 flags=0 cpu=8 credit=115 [w=2000,cap=0]
(XEN) CPU[09] current=d19v1, curr=d19v1, prev=NULL
(XEN) CPU[09] nr_run=1, sort=996335, sibling={9}, core={8-15}
(XEN)   run: [19.1] pri=-2 flags=0 cpu=9 credit=-241 [w=256,cap=0]
(XEN)     1: [32767.9] pri=-64 flags=0 cpu=9
(XEN) CPU[10] current=d[IDLE]v10, curr=d[IDLE]v10, prev=NULL
(XEN) CPU[10] nr_run=0, sort=996334, sibling={10}, core={8-15}
(XEN) CPU[11] current=d[IDLE]v11, curr=d[IDLE]v11, prev=NULL
(XEN) CPU[11] nr_run=0, sort=996331, sibling={11}, core={8-15}
(XEN) CPU[12] current=d[IDLE]v12, curr=d[IDLE]v12, prev=NULL
(XEN) CPU[12] nr_run=0, sort=996333, sibling={12}, core={8-15}
(XEN) CPU[13] current=d[IDLE]v13, curr=d[IDLE]v13, prev=NULL
(XEN) CPU[13] nr_run=0, sort=996334, sibling={13}, core={8-15}
(XEN) CPU[14] current=d0v14, curr=d0v14, prev=NULL
(XEN) CPU[14] nr_run=1, sort=990383, sibling={14}, core={8-15}
(XEN)   run: [0.14] pri=0 flags=0 cpu=14 credit=-514 [w=2000,cap=0]
(XEN)     1: [32767.14] pri=-64 flags=0 cpu=14
(XEN) CPU[15] current=d0v6, curr=d0v6, prev=NULL
(XEN) CPU[15] nr_run=1, sort=996335, sibling={15}, core={8-15}
(XEN)   run: [0.6] pri=-2 flags=0 cpu=15 credit=-177 [w=2000,cap=0]
(XEN)     1: [32767.15] pri=-64 flags=0 cpu=15
```

I attempt to get '*' but that blocked my serial console, at least I was not 
able to interact with it few minutes later. I'll try to get other info too. 
I've also uploaded the piece of this huge '*' dump here: 
https://gist.github.com/fepitre/36923fbc08cc2fd8bdb59b81e73a6c2e

Regards

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