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Subject: Re: Ryzen issues on FreeBSD ? (with sort of workaround)
To: Mike Tancsa <mike@sentex.net>, Don Lewis <truckman@FreeBSD.org>
Cc: eric@vangyzen.net, freebsd-stable@freebsd.org, freebsd@hda3.com,
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From: Pete French <petefrench@ingresso.co.uk>
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Date: Sun, 3 Jun 2018 20:36:28 +0100
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On 03/06/2018 18:49, Mike Tancsa wrote:

> 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.

Agreed about the performance hit turning off SMP! Am hoping its a 
temporary thing, and if we can show it *is* SMP then maybe that will 
hepl with a fix, as there cant be that many places where SMP is handled 
differently to real cores I would think. If you could test then that 
would be great!

cheers,

-pete.