Bug 463529

Summary:	[LTC 6.0 FEAT] 201027:Tickless idle for Power
Product:	Red Hat Enterprise Linux 6	Reporter:	IBM Bug Proxy <bugproxy>
Component:	kernel	Assignee:	Kevin W Monroe <kmonroe>
Status:	CLOSED CURRENTRELEASE	QA Contact:	Martin Jenner <mjenner>
Severity:	high	Docs Contact:
Priority:	high
Version:	6.0	CC:	ejratl, notting, peterm
Target Milestone:	alpha	Keywords:	FutureFeature
Target Release:	6.0
Hardware:	ppc64
OS:	All
Whiteboard:
Fixed In Version:		Doc Type:	Enhancement
Doc Text:		Story Points:	---
Clone Of:		Environment:
Last Closed:	2009-09-23 22:08:21 UTC	Type:	---
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:	356741, 515068, 525727

Description IBM Bug Proxy 2008-09-23 20:30:58 UTC

=Comment: #0=================================================
Emily J. Ratliff <emilyr.com> - 2008-09-16 17:55 EDT
1. Feature Overview:
Feature Id:	[201027]
a. Name of Feature:	Tickless idle for Power
b. Feature Description
add code for tickless idle loop in kernel

2. Feature Details:
Sponsor:	PPC
Architectures:
ppc64

Arch Specificity: Purely Arch Specific Code
Affects Installer: Yes
Affects Core Kernel: Yes
Delivery Mechanism: Direct from community
Category:	Kernel
Request Type:	Kernel - Enhancement from IBM
d. Upstream Acceptance:	Accepted
Sponsor Priority	1
f. Severity: High
IBM Confidential:	no
Code Contribution:	IBM code
g. Component Version Target:	2.6.24

3. Business Case
The tickless idle loop should bring cooler CPUs as well as power savings.

4. Primary contact at Red Hat: 
John Jarvis
jjarvis

5. Primary contacts at Partner:
Project Management Contact:
Michael Hohnbaum, hbaum.com, 503-578-5486

Technical contact(s):
Tony Breeds, tbreeds.com

Comment 1 Bill Nottingham 2008-10-02 19:20:05 UTC

RHEL 6 will include a kernel newer than 2.6.24, so this should not be a problem.

The feature requested has already been accepted into the upstream code base
planned for the next major release of Red Hat Enterprise Linux.

When the next milestone release of Red Hat Enterprise Linux 6 is available,
please verify that the feature requested is present and functioning as
desired.

Comment 2 IBM Bug Proxy 2009-03-02 19:51:43 UTC

it is in 2.6.24
sha1 id: 1ad749980a5fda46f7ec920d8409ddcc89b38714

Comment 3 Kevin W Monroe 2009-09-23 22:08:21 UTC

Closing - included in Red Hat Enterprise Linux 6.

Comment 4 IBM Bug Proxy 2009-11-16 18:31:01 UTC

------- Comment From luciojhc.com 2009-11-16 13:20 EDT-------
Feature verified with RHEL6 20091110 build.

[root@kia-lp4 ~]# egrep '\.(nohz_mode|hres_active)' /proc/timer_list  | sort -u
.hres_active    : 1
.nohz_mode      : 2

Comment 5 IBM Bug Proxy 2010-05-04 00:11:56 UTC

------- Comment From tonyb.com 2010-05-03 20:01 EDT-------
(In reply to comment #7)
> Feature verified with RHEL6 20091110 build.
>
> [root@kia-lp4 ~]# egrep '\.(nohz_mode|hres_active)' /proc/timer_list  | sort -u
>   .hres_active    : 1
>   .nohz_mode      : 2

Verified on Snap1

[root@alien4 ~]# grep NO_HZ /boot/config-2.6.32-19.el6.ppc64
CONFIG_NO_HZ=y
[root@alien4 ~]# grep nohz_mode /proc/timer_list  | sort | uniq -c
32   .nohz_mode      : 2