not a reproducable regression [Was :Re: bhyve ahcich0: Timeout on slot 0 port 0,, regression with stable/11->releng/11.1]

[Harry Schmalzbauer]

 Bezüglich Harry Schmalzbauer's Nachricht vom 30.06.2017 21:22 (localtime):
>  Bezüglich Harry Schmalzbauer's Nachricht vom 30.06.2017 21:17 (localtime):
>>  Hello,
>>
>> on releng/11.1 I noticed a severe performace degradation during file
>> unlinking in a FreeBSD guest. Host was running quiet recent stable/11
>> before.
>>
>> On the host, the vm is started with
>> ahci,hd:/dev/adaN
>>
>> The guest attaches:
>> ada0 at ahcich0 bus 0 scbus0 target 0 lun 0
>> ada0: <BHYVE SATA DISK 001> ACS-2 ATA SATA 3.x device
>>
>> The geust has very high Sys-load during unlinking (50-75%@2 cores).
>> Also, the host logs these errors:
> Sorry, not the host logs these errors, but the guest, obviously.
>

After a reboot, I couldn't reproduce the timeouts, nor the completion
time multiplication. It takes ~8 minutes like it alwas was… Sorry for
late falsifying.

I'm still wondering what these timeout error codes translate to.

And I can still see very high CPU load in the guest during unlinking
(obj-tree of usr/src).
While systat reports less than 10irqs/s for AHCI0, "intr" consumes
30-800% at times (with 4 vCPUs).
"bufdaemon" and "rm" consume 10-100% each.
So total average is about 2 completely loaded cores for 'rm' running in
a FreeBSD guest.

Any hints regarding timeout codes or how to trace where CPU cycles drain
are highly appreciated!

Thanks,

-harry