Note: This bug is displayed in read-only format because
the product is no longer active in Red Hat Bugzilla.
RHEL Engineering is moving the tracking of its product development work on RHEL 6 through RHEL 9 to Red Hat Jira (issues.redhat.com). If you're a Red Hat customer, please continue to file support cases via the Red Hat customer portal. If you're not, please head to the "RHEL project" in Red Hat Jira and file new tickets here. Individual Bugzilla bugs in the statuses "NEW", "ASSIGNED", and "POST" are being migrated throughout September 2023. Bugs of Red Hat partners with an assigned Engineering Partner Manager (EPM) are migrated in late September as per pre-agreed dates. Bugs against components "kernel", "kernel-rt", and "kpatch" are only migrated if still in "NEW" or "ASSIGNED". If you cannot log in to RH Jira, please consult article #7032570. That failing, please send an e-mail to the RH Jira admins at rh-issues@redhat.com to troubleshoot your issue as a user management inquiry. The email creates a ServiceNow ticket with Red Hat. Individual Bugzilla bugs that are migrated will be moved to status "CLOSED", resolution "MIGRATED", and set with "MigratedToJIRA" in "Keywords". The link to the successor Jira issue will be found under "Links", have a little "two-footprint" icon next to it, and direct you to the "RHEL project" in Red Hat Jira (issue links are of type "https://issues.redhat.com/browse/RHEL-XXXX", where "X" is a digit). This same link will be available in a blue banner at the top of the page informing you that that bug has been migrated.
Description of problem:
mpstat on intermittently shows incorrect CPU usage on ALL CPU field for "iowait"
Version-Release number of selected component (if applicable):
All versions affected, affected customer here used sysstat-11.7.3-5.el8
How reproducible:
not easily
Steps to Reproduce:
1. On a bugger system, i.e. 32 cores, execute mpstat, for example "mpstat -P ALL 1 1" or "mpstat -P ALL 1 3600"
Actual results:
Total CPU usage (%iowait) is 97.10%.
01:17:04 AM CPU %usr %nice %sys %iowait %irq %soft %steal %guest %gnice %idle
01:17:05 AM all 0.00 0.00 0.01 _97.10_ 0.00 0.00 0.00 0.00 0.00 2.88
01:17:05 AM 17 0.00 0.00 0.00 _99.91_ 0.00 0.00 0.00 0.00 0.00 0.09
Expected results:
Total CPU usage (%iowait) should be a value which is divided by 32, because the system has 32 CPUs.
01:17:04 AM CPU %usr %nice %sys %iowait %irq %soft %steal %guest %gnice %idle
01:17:05 AM all 0.00 0.00 0.01 _3.12_ 0.00 0.00 0.00 0.00 0.00 2.88
01:17:05 AM 17 0.00 0.00 0.00 _99.91_ 0.00 0.00 0.00 0.00 0.00 0.09
Additional info:
- Issue exists also in upstream
- a build of mpstat with the following commit was reported to fix
the issue for the customer:
https://github.com/sysstat/sysstat/commit/1f5949d4a6fcb33065dbb1d509f356db039998ed
So, requesting this commit into RHEL.
Workaround exists, Performance Co-Pilot (PCP) provides independent code which
gathers metrics and provides with "pcp mpstat" an independent client of similar
output, which does not show the issue.
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: sysstat security and bug fix 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-2023:7010