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Bug 1884297

Summary: kube-apiserver consumes higher CPU in 4.6 compared to other releases
Product: OpenShift Container Platform Reporter: Prashanth Sundararaman <psundara>
Component: kube-apiserverAssignee: Abu Kashem <akashem>
Status: CLOSED CURRENTRELEASE QA Contact: Ke Wang <kewang>
Severity: medium Docs Contact:
Priority: low    
Version: 4.6CC: amccrae, aos-bugs, danili, dslavens, mfojtik, sttts, xxia
Target Milestone: ---Flags: mfojtik: needinfo?
Target Release: 4.7.0   
Hardware: s390x   
OS: Unspecified   
Whiteboard: multi-arch LifecycleReset
Fixed In Version: Doc Type: No Doc Update
Doc Text:
Story Points: ---
Clone Of: Environment:
Last Closed: 2021-02-03 15:53:33 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: 1881153    
Attachments:
Description Flags
cpu.png
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pprof_4.6.pdf
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pprof_4.4.pdf none

Description Prashanth Sundararaman 2020-10-01 15:25:19 UTC 
Starting a new BZ spinning off from: https://bugzilla.redhat.com/show_bug.cgi?id=1878770.

On 4.6 installs on s390x there have been reports of high cpu consumption even when the system has been idling. I have attached a screenshot of the idle consumption of CPU on a zVM system.

On recommendation from the apiserver team i have also collected a pprof profile on 4.6 and also collected one on 4.4 just for comparison.

While this problem as been observed on s390x, I am not sure if it is an issue across the board for other arches as well.
Comment 1 Prashanth Sundararaman 2020-10-01 15:26:59 UTC 
Created attachment 1718197 [details]
cpu.png
Comment 2 Prashanth Sundararaman 2020-10-01 15:27:32 UTC 
Created attachment 1718198 [details]
pprof_4.6.pdf
Comment 3 Prashanth Sundararaman 2020-10-01 15:27:56 UTC 
Created attachment 1718199 [details]
pprof_4.4.pdf
Comment 4 Michal Fojtik 2020-10-31 16:12:06 UTC 
This bug hasn't had any activity in the last 30 days. Maybe the problem got resolved, was a duplicate of something else, or became less pressing for some reason - or maybe it's still relevant but just hasn't been looked at yet. As such, we're marking this bug as "LifecycleStale" and decreasing the severity/priority. If you have further information on the current state of the bug, please update it, otherwise this bug can be closed in about 7 days. The information can be, for example, that the problem still occurs, that you still want the feature, that more information is needed, or that the bug is (for whatever reason) no longer relevant. Additionally, you can add LifecycleFrozen into Keywords if you think this bug should never be marked as stale. Please consult with bug assignee before you do that.
Comment 5 Dan Li 2021-02-03 15:12:41 UTC 
Reviewed. 

Hi @Prashanth, do we need to keep this bug open as it is marked as LifecycleStale?
Comment 6 Michal Fojtik 2021-02-03 15:46:06 UTC 
The LifecycleStale keyword was removed because the bug got commented on recently.
The bug assignee was notified.
Comment 7 Prashanth Sundararaman 2021-02-03 15:53:33 UTC 
checked on 4.7 and the CPU consumption is much better. closing this.