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Bug 1015726

Summary: Performance tool user guide - Please document that systems using HPET as a clocksource are slow.
Product: Red Hat Enterprise Linux 7 Reporter: Jiri Hladky <jhladky>
Component: doc-Technical_NotesAssignee: Milan Navratil <mnavrati>
Status: CLOSED WONTFIX QA Contact: ecs-bugs
Severity: medium Docs Contact:
Priority: high    
Version: 7.0CC: apetrova, jhladky
Target Milestone: rcKeywords: Documentation
Target Release: ---   
Hardware: All   
OS: Linux   
Whiteboard:
Fixed In Version: Doc Type: Bug Fix
Doc Text:
Story Points: ---
Clone Of: Environment:
Last Closed: 2016-01-19 16:17:44 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:

Description Jiri Hladky 2013-10-04 23:47:57 UTC
Description of problem:

Performance tool user guide 

Please document that systems using HPET as a clocksource are slow. The performance regression depends on the load and is known to be as high as 25% compared to RHEL6.5. Vendors that want to make their system fast, can fix the TSC clocksource for those systems (either in firmware, or in the kernel).

Comment 1 Jiri Hladky 2013-10-04 23:49:53 UTC
Please see BZ 971925 for technical details

Comment 3 Jiri Hladky 2013-10-05 00:04:38 UTC
Comment: this affects mainly RHEL7 and newer releases

Comment 6 Jiri Hladky 2014-02-04 08:18:39 UTC
Hi Laura,

yes, you are right, a technical note would be the best fit for this kind of information.

Thank you
Jirka

Comment 7 Laura Bailey 2014-02-04 20:05:31 UTC
No worries, Jirka, popping this into the tech notes component. :)