Bug 707989

Summary:	cpuspeed should reset to max frequency when "service cpuspeed stop" is issued
Product:	Red Hat Enterprise Linux 5	Reporter:	yossig
Component:	cpuspeed	Assignee:	Petr Šabata <psabata>
Status:	CLOSED WONTFIX	QA Contact:	Red Hat Kernel QE team <kernel-qe>
Severity:	low	Docs Contact:
Priority:	low
Version:	5.6	CC:	ovasik, yossig
Target Milestone:	rc
Target Release:	---
Hardware:	Unspecified
OS:	Unspecified
Whiteboard:
Fixed In Version:		Doc Type:	Bug Fix
Doc Text:		Story Points:	---
Clone Of:
Clones:	709049 (view as bug list)		Environment:
Last Closed:	2013-08-12 14:45:10 UTC	Type:	---
Regression:	---	Mount Type:	---
Documentation:	---	CRM:
Verified Versions:		Category:	---
oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:
Bug Depends On:
Bug Blocks:	709049

Description yossig 2011-05-26 13:57:15 UTC

Description of problem:


If cpuspeed was enabled on a system and the user issues "service cpuspeed stop"  followed by "chkconfig cpuspeed off",  the cpu frequency of the cpus is left at the current frequency that was set by the kernel.

So if the speed was reduced by the kernel to a lower rate, it is not reset to the maximum rate.

I think the common user may miss this and get poor performance of his system until he reboots his system.

There is an easy way to work around this but i suggest that this behavior should be changed.



Version-Release number of selected component (if applicable):
cpuspeed-1.2.1-9.el5 and earlier

How reproducible:
enable cpuspeed cause it to reduce cpu frequency and then issue stop cpuspeed.
CPU frequency stays as is.

I am not sure I can call it a bug, maybe more a change to reduce the risk of a user to stay with a system working unexpectedly slow. 

Thank you!

Comment 1 Petr Šabata 2011-05-26 14:14:01 UTC

Thanks for the report.

Indeed, switching to the highest frequency available in scaling_available_frequencies would be probably the best idea.

Comment 5 RHEL Program Management 2013-05-01 06:41:57 UTC

This request was evaluated by Red Hat Product Management for
inclusion in the current release of Red Hat Enterprise Linux.
Because the affected component is not scheduled to be updated
in the current release, Red Hat is unable to address this
request at this time.

Red Hat invites you to ask your support representative to
propose this request, if appropriate, in the next release of
Red Hat Enterprise Linux.

Comment 6 Petr Šabata 2013-08-12 14:45:10 UTC

I'm going to close this as a WONTFIX.

The highest available frequency isn't necessarily the state we were in before we started the cpuspeed service and setting that might even be a) dangerous on some systems, b) impossible in case the limits have been altered externally and the kernel isn't aware of that.  Because of the latter, I don't think remembering the state in the moment of our start would be beneficial either.

We could possibly introduce new configuration settings for what frequency and governor we should switch to upon exiting but I don't find this too useful.