Hi
Please, help me to solve the following problem:
- guest runs perfect with 1 CPU assigned, but runs very slow (up to total hung) when multiple CPU are assigned.
Host:
- CPU: AMD Epyc 2401P
- MB: MZ31-AR0 (firmware F03e)
- OS: CentOS 7 (1708) / FreeBSD 11.1-RELEASE (p6) (tried with both OSes - no difference)
- VirtualBox 5.2.6
Guests:
- Windows 2008 R2 / 2016
I've tried different Paravirtualization Interfaces, tried to turn Hardware Virtualization on/off - no difference.
I've tried to disable SMT Mode as well (i.e. disable hyper-threading in BIOS).
Any suggestions, recommendations, whatever, please.
Logs and vbox configs are attached.
Thank you
VirtualBox on AMD EPYC - very slow guest running
VirtualBox on AMD EPYC - very slow guest running
- Attachments
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- vbox_amd-epyc.zip
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socratis
- Site Moderator
- Posts: 27329
- Joined: 22. Oct 2010, 11:03
- Primary OS: Mac OS X other
- VBox Version: PUEL
- Guest OSses: Win(*>98), Linux*, OSX>10.5
- Location: Greece
Re: VirtualBox on AMD EPYC - very slow guest running
Can I have the computer shipped to me (as a loan) until I solve this? I don't have readily available a 24-core, 256 GB RAM system right now... 
You're on FreeBSD. They make their own fork. They're usually pretty good about keeping up, but we're not sure about the changes they make to the original VirtualBox.
You're on FreeBSD. They make their own fork. They're usually pretty good about keeping up, but we're not sure about the changes they make to the original VirtualBox.
- I see you have the logs for 1- or 16-CPU configuration. I assume you tried values in between, right?
- Can you quantify "very slow"?
- Do not change the Paravirtualization options. Stick with the defaults.
- Funny that you mentioned the SMT mode. Did you read this? "Does Disabling SMT on a Ryzen 7 CPU Improves its Performance?"
Do NOT send me Personal Messages (PMs) for troubleshooting, they are simply deleted.
Do NOT reply with the "QUOTE" button, please use the "POST REPLY", at the bottom of the form.
If you obfuscate any information requested, I will obfuscate my response. These are virtual UUIDs, not real ones.
Do NOT reply with the "QUOTE" button, please use the "POST REPLY", at the bottom of the form.
If you obfuscate any information requested, I will obfuscate my response. These are virtual UUIDs, not real ones.
Re: VirtualBox on AMD EPYC - very slow guest running
Ok
Provider had updated motherboard firmware. Will check now - if it helps.
If not - I'll install CentOS and contact you for help.
Thank you.
Provider had updated motherboard firmware. Will check now - if it helps.
If not - I'll install CentOS and contact you for help.
Thank you.
Re: VirtualBox on AMD EPYC - very slow guest running
No luck 
With 16 cores the installation takes much longer. First login takes some minutes and sometimes system falls into BSOD.
Sent you PMsocratis wrote:Can I have the computer shipped to me (as a loan) until I solve this? I don't have readily available a 24-core, 256 GB RAM system right now...
Yes. Tried 2, 4, 8, 20. It is funny: the more CPUs assigned to guest - the slower guest running...socratis wrote:I see you have the logs for 1- or 16-CPU configuration. I assume you tried values in between, right?
With one core the installation and first login takes just a few minutes. Guest system responses very quick, etc.socratis wrote:Can you quantify "very slow"?
With 16 cores the installation takes much longer. First login takes some minutes and sometimes system falls into BSOD.
I had read other topics/articles where system with AMD Ryzen/Epyc fails spontaneously with SMT enabled. So I've tried to disable SMT. But it changed nothing in my case.socratis wrote:Funny that you mentioned the SMT mode. Did you read this? "Does Disabling SMT on a Ryzen 7 CPU Improves its Performance?"
Re: VirtualBox on AMD EPYC - very slow guest running
Looks line no chances.
With 1 CPU assigned guest works good.
With more than 1 CPU assigned guest falls into BSOD:
"DPC WATCHDOG VIOLATION"
Will try latest stable VB build...
With 1 CPU assigned guest works good.
With more than 1 CPU assigned guest falls into BSOD:
"DPC WATCHDOG VIOLATION"
Will try latest stable VB build...
Re: VirtualBox on AMD EPYC - very slow guest running
Tried latest test build 5.2.x revision 120822.
No changes.
No changes.