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.
Bug 1259452 - tuned-profiles-nfv: lapic_timer_adv_ns cache not working
Summary: tuned-profiles-nfv: lapic_timer_adv_ns cache not working
Keywords:
Status: CLOSED ERRATA
Alias: None
Product: Red Hat Enterprise Linux 7
Classification: Red Hat
Component: tuned
Version: 7.2
Hardware: Unspecified
OS: Unspecified
high
unspecified
Target Milestone: rc
: ---
Assignee: Jaroslav Škarvada
QA Contact: Tereza Cerna
URL:
Whiteboard:
Depends On:
Blocks: kvm-rt-tuned 1273048 1282567
TreeView+ depends on / blocked
 
Reported: 2015-09-02 15:56 UTC by Luiz Capitulino
Modified: 2016-11-04 07:25 UTC (History)
10 users (show)

Fixed In Version: tuned-2.5.1-5.el7
Doc Type: Bug Fix
Doc Text:
Clone Of:
: 1282567 (view as bug list)
Environment:
Last Closed: 2016-11-04 07:25:01 UTC
Target Upstream Version:
Embargoed:
tcerna: needinfo-

Attachments (Terms of Use)


Links
System ID Private Priority Status Summary Last Updated
Red Hat Product Errata RHBA-2016:2479 0 normal SHIPPED_LIVE tuned bug fix and enhancement update 2016-11-03 14:08:42 UTC

Description Luiz Capitulino 2015-09-02 15:56:23 UTC 
Description of problem:

Every time I boot my KVM-RT host, I can observe that the file /sys/module/kvm/parameters/lapic_timer_advance_ns keeps changing for minutes. Even after the system is fully booted.

Version-Release number of selected component (if applicable): tuned-profiles-nfv-2.5.1-3.el7.noarch


How reproducible:


Steps to Reproduce:
1. Boot a host with the realtime-virtual-host profile setup
2. After boot, run:

 # watch -n1 cat /sys/module/kvm/parameters/lapic_timer_advance_ns

3. Check the file contents changing every few seconds or so

Actual results:


Expected results:


Additional info:
Comment 1 Luiz Capitulino 2015-09-02 15:56:53 UTC 
I've debugged this down to two bugs in the code that implements lapic_timer_adv_ns cache caching. The patch below should fix them:

diff --git a/profiles/realtime-virtual-host/script.sh b/profiles/realtime-virtual-host/script.sh
index 9970b8e..161052c 100755
--- a/profiles/realtime-virtual-host/script.sh
+++ b/profiles/realtime-virtual-host/script.sh
@@ -27,7 +27,7 @@ start() {
         curmodel=`cat /proc/cpuinfo | grep "model name" | cut -f 2 -d ":" | uniq`
         genmodel=`cat lapic_timer_adv_ns.cpumodel`
 
-        if [ "$cpumodel" != "$genmodel" ]; then
+        if [ "$curmodel" != "$genmodel" ]; then
             rm -f lapic_timer_adv_ns
             rm -f lapic_timer_adv_ns.cpumodel
         fi
@@ -43,7 +43,7 @@ start() {
              if [ $? -eq 0 ]; then
                   echo `cat $tempdir/opt.out | cut -f 2 -d ":"` > ./lapic_timer_adv_ns
                   curmodel=`cat /proc/cpuinfo | grep "model name" | cut -f 2 -d ":" | uniq`
-                  echo $curmodel > lapic_timer_adv_ns.cpumodel
+                  echo "$curmodel" > lapic_timer_adv_ns.cpumodel
              fi
         fi
     fi
Comment 4 Jaroslav Škarvada 2015-11-16 16:30:10 UTC 
Upstream commit fixing the problem:
https://git.fedorahosted.org/cgit/tuned.git/commit/?id=cb826c1e38a3bf68a1c169a2665d2edab72abb2d
Comment 13 errata-xmlrpc 2016-11-04 07:25:01 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, 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://rhn.redhat.com/errata/RHBA-2016-2479.html
Note You need to log in before you can comment on or make changes to this bug.