Ryzen issues on FreeBSD ? (with sort of workaround)

[Mike Tancsa]

On 6/3/2018 1:10 PM, Pete French wrote:
> 
>> The compile bug has been fixed for me.  However, last I checked I can
>> still freeze a system by generating a lot of network traffic between VMs
>> in either bhyve or virtbox.  Its been a while since I tested (couple of
>> months) but I dont recall anything obviously committed that highlighted
>> that issue.  Note this is on Epyc and Ryzen boxes
> 
> Yes, it was your iperf3 tests which enable me to freeze the system with
> SMP enabled. With SMP disabled it works fine, however. have you tried
> that at all ? The only other settings I ahve are the global C-states
> and cool-n-quiet being disabled. I dont really care about either so
> havent tested re-enabling them.

I have c-states disabled on the ryzen both for FreeBSD and Linux.  To
disable SMP on the Epyc doesnt seem to be possible. But then again kill
off 31 cores is a heavy cost to pay for stability :(  When I am back at
the office, I will see if a recent checkout of HEAD still freezes the Epyc.

	---Mike


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Mike Tancsa, tel +1 519 651 3400 x203
Sentex Communications, mike at sentex.net
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