Bug 250516

Summary:	Poor performance if running as guest OS on QEMU
Product:	Base System	Reporter:	Charlie <cdang_2000>
Component:	misc	Assignee:	freebsd-virtualization (Nobody) <virtualization>
Status:	New ---
Severity:	Affects Some People	CC:	freebsd, rainer, rob2g2-freebsd
Priority:	---
Version:	12.1-RELEASE
Hardware:	Any
OS:	Any

Description Charlie 2020-10-22 01:46:06 UTC

Hi,

I am new here and trying to find answers to the issue described below.

We make PCI chip which mainly plugged in Linux systems.
If I installed FreeBSD 12.1 on actual HW (i.e. x86), PCI throughput is fine and compatible with other Linux OSes like Ubuntu or CentOS.

But, if I run it as a guest OS on QEMU, then the PCI throughput is very very low. This is compared to the same tests I run on Ubuntu or CentOS as guest OS on the same QEMU.

So, I would like to know:
1. Do you have any report about the same situation: PCI throughput is very low if FreeBSD runs as guest OS on QEMU?
2. What kind of data you need me to capture in order for you to debug further?

Please let me know.

Thanks.

Comment 1 Mark Linimon freebsd_committer

2021-06-30 00:14:15 UTC

^Triage: reassign.  I'm sorry that this did not get done sooner.

Comment 2 rainer 2021-06-30 07:01:36 UTC

Hi,

I have the same problem, running FreeBSD as a guest in Openstack (which uses kvm/qemu).

I actually had the same problem running it under Xen. So it's been going like that for at least five years.


See here:

https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=238733

Comment 3 Frank Wall 2021-11-24 15:41:39 UTC

I don't have this issue when using FreeBSD 13.0 on oVirt (also based on KVM/qemu). So I'm wondering how you measure and compare the performance between FreeBSD and Linux.