Bug 2218644 - query-stats QMP command interrupts vcpus, the Max Latencies could be more than 100us (rhel 9.3.0 clone)
Summary: query-stats QMP command interrupts vcpus, the Max Latencies could be more tha...
Keywords:
Status: VERIFIED
Alias: None
Product: Red Hat Enterprise Linux 9
Classification: Red Hat
Component: qemu-kvm
Version: 9.3
Hardware: x86_64
OS: Unspecified
high
high
Target Milestone: rc
: ---
Assignee: Marcelo Tosatti
QA Contact: Gu Nini
URL:
Whiteboard:
: 2214884 (view as bug list)
Depends On: 2214884
Blocks: 2221219
TreeView+ depends on / blocked
 
Reported: 2023-06-29 17:53 UTC by Marcelo Tosatti
Modified: 2023-07-25 03:22 UTC (History)
12 users (show)

Fixed In Version: qemu-kvm-8.0.0-7.el9
Doc Type: If docs needed, set a value
Doc Text:
Clone Of: 2214884
: 2221219 (view as bug list)
Environment:
Last Closed:
Type: ---
Target Upstream Version:
Embargoed:

Attachments (Terms of Use)


Links
System ID Private Priority Status Summary Last Updated
Gitlab redhat/centos-stream/src qemu-kvm merge_requests 177 0 None opened kvm: reuse per-vcpu stats fd to avoid vcpu interruption 2023-06-29 18:05:15 UTC
Red Hat Issue Tracker RHELPLAN-161202 0 None None None 2023-06-29 17:54:59 UTC

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.
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