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Bug 1250750

Summary: evaluate realtime performance implications of turning on CONFIG_CGROUP_SCHED in realtime kernel
Product: Red Hat Enterprise Linux 7 Reporter: Clark Williams <williams>
Component: kernel-rtAssignee: Steven Rostedt <srostedt>
Status: CLOSED ERRATA QA Contact: Jiri Kastner <jkastner>
Severity: high Docs Contact:
Priority: high    
Version: 7.3CC: bhu, hhuang, pagupta, williams
Target Milestone: rc   
Target Release: 7.3   
Hardware: x86_64   
OS: Linux   
Whiteboard:
Fixed In Version: Doc Type: Bug Fix
Doc Text:
Story Points: ---
Clone Of: Environment:
Last Closed: 2016-11-03 19:35:42 UTC Type: Bug
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:    
Bug Blocks: 1274397, 1282922, 1313485    

Description Clark Williams 2015-08-05 21:55:01 UTC 
Current RT kernel does not have CGROUP_SCHED config enabled, but may be needed down the road. Anecdotal evidence shows that that there is a 4-8us max latency penalty when testing with rteval. 

We need to determine if there is a consistent increase to max latency with CGROUP_SCHED enabled and if so, are there changes we can make to reduce the effect.
Comment 1 Clark Williams 2015-09-01 15:13:38 UTC 
Pushing out to 7.3
Comment 2 Beth Uptagrafft 2015-09-02 17:17:37 UTC 
Moving to 7.3
Comment 3 Clark Williams 2016-06-23 21:36:17 UTC 
CONFIG_CGROUP_SCHED enabled in kernel-rt-3.10.0-382.rt56.363.el7. No significant performance loss noted in rteval runs.
Comment 7 errata-xmlrpc 2016-11-03 19:35:42 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/RHSA-2016-2584.html