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_Notes	Assignee:	Milan Navratil <mnavrati>
Status:	CLOSED WONTFIX	QA Contact:	ecs-bugs
Severity:	medium	Docs Contact:
Priority:	high
Version:	7.0	CC:	apetrova, jhladky
Target Milestone:	rc	Keywords:	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:

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. :)