Bug 2218644

Summary:	query-stats QMP command interrupts vcpus, the Max Latencies could be more than 100us (rhel 9.3.0 clone)
Product:	Red Hat Enterprise Linux 9	Reporter:	Marcelo Tosatti <mtosatti>
Component:	qemu-kvm	Assignee:	Marcelo Tosatti <mtosatti>
qemu-kvm sub component:	General	QA Contact:	Gu Nini <ngu>
Status:	CLOSED ERRATA	Docs Contact:
Severity:	high
Priority:	high	CC:	alougovs, chayang, coli, jinzhao, junzhao, juzhang, lijin, ngu, pbonzini, pezhang, virt-maint, ymankad
Version:	9.3	Keywords:	CustomerScenariosInitiative, Triaged, ZStream
Target Milestone:	rc
Target Release:	---
Hardware:	x86_64
OS:	Unspecified
Whiteboard:
Fixed In Version:	qemu-kvm-8.0.0-7.el9	Doc Type:	If docs needed, set a value
Doc Text:		Story Points:	---
Clone Of:	2214884
Clones:	2221219 (view as bug list)		Environment:
Last Closed:	2023-11-07 08:28:05 UTC	Type:	---
Regression:	---	Mount Type:	---
Documentation:	---	CRM:
Verified Versions:		Category:	---
oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:
Embargoed:
Bug Depends On:	2214884
Bug Blocks:	2221219

Description Marcelo Tosatti 2023-06-29 17:53:56 UTC

RHEL 9.3.0 / CentOS clone

+++ This bug was initially created as a clone of Bug #2214884 +++

Description of problem:
Under ocp4.13/ocp-v 4.13.1-188 env, the real time worker node is installed with RHCOS based on RHEL9.2, it's found "# Max Latencies: 00090 00096 00141" when run 1 hour cyclictest, while a maximum of 50us is acceptable. From Marcelo, it's caused by "query-stats QMP command interrupts vcpus.", "[PATCH] kvm: reuse per-vcpu stats fd to avoid vcpu interruption" was submitted.

Version-Release number of selected component (if applicable):
Host kernel: Scratch kernel 5.14.0-284.13.1.rt14.298kvmrtv1.el9_2.x86_64 
Guest kernel: Scratch kernel 5.14.0-284.13.1.rt14.298kvmrtv1.el9_2.x86_64
Qemu: qemu-kvm-core-7.2.0-14.el9_2.x86_64

How reproducible:
100%

Steps to Reproduce:
1. 
2.
3.

Actual results:

Expected results:

Additional info:

Comment 2 John Ferlan 2023-06-30 15:07:20 UTC

Adding zstream and ZTR=9.2.0, see bug 2214884 for details, especially https://bugzilla.redhat.com/show_bug.cgi?id=2214884#c2

Comment 4 Miroslav Rezanina 2023-07-03 07:25:33 UTC

*** Bug 2214884 has been marked as a duplicate of this bug. ***

Comment 9 Marcelo Tosatti 2023-07-10 11:19:30 UTC

Test steps to verify bug:

1) Run qemu-kvm in parallel with rt-trace-bpf, with isolated vcpu.

2) Run query-stats command on QMP 
(https://patchew.org/Libvirt/20220624081449.70085-1-natto@weirdnatto.in/20220624081449.70085-3-natto@weirdnatto.in/), should see
IPIs to pcpu where isolated vcpu runs.

3) with fixed qemu-kvm, should be able to run query-stats QMP command and not see the IPIs.

Comment 10 Yanan Fu 2023-07-11 09:11:35 UTC

QE bot(pre verify): Set 'Verified:Tested,SanityOnly' as gating/tier1 test pass.

Comment 18 errata-xmlrpc 2023-11-07 08:28:05 UTC

Since the problem described in this bug report should be
resolved in a recent advisory, it has been closed with a
resolution of ERRATA.

For information on the advisory (Moderate: qemu-kvm security, bug fix, and enhancement update), and where to find the updated
files, follow the link below.

If the solution does not work for you, open a new bug report.

https://access.redhat.com/errata/RHSA-2023:6368