Bug 437672 – 1000Hz timer still active on tickless kernel

Bug 437672 - 1000Hz timer still active on tickless kernel

Summary:	1000Hz timer still active on tickless kernel

Status:	CLOSED CANTFIX

Aliases:	None

Product:	Fedora
Classification:	Fedora
Component:	kernel (Show other bugs)
Sub Component:
Version:	8
Hardware:	x86_64 Linux

Priority	low Severity low
Target Milestone:	---
Target Release:	---
Assigned To:	Kernel Maintainer List
QA Contact:	Fedora Extras Quality Assurance
Docs Contact:

URL:
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Depends On:
Blocks:
	Show dependency tree / graph

Reported:	2008-03-15 22:47 EDT by Michael Cronenworth
Modified:	2008-03-15 23:23 EDT (History)
CC List:	0 users

See Also:
Fixed In Version:
Doc Type:	Bug Fix
Doc Text:
Story Points:	---
Clone Of:
Environment:
Last Closed:	2008-03-15 23:23:22 EDT
Type:	---
Regression:	---
Mount Type:	---
Documentation:	---
CRM:
Verified Versions:
Category:	---
oVirt Team:	---
RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---

Attachments	(Terms of Use)
dmesg.txt (28.18 KB, text/plain) 2008-03-15 22:47 EDT, Michael Cronenworth	no flags	Details
lspci.txt (26.04 KB, text/plain) 2008-03-15 22:48 EDT, Michael Cronenworth	no flags	Details
powertop.txt (792 bytes, text/plain) 2008-03-15 22:50 EDT, Michael Cronenworth	no flags	Details
Add an attachment (proposed patch, testcase, etc.)

Groups: None (edit)

Description Michael Cronenworth 2008-03-15 22:47:35 EDT

Description of problem: Powertop reports that a 1000Hz timer is still active.
This prevents the CPU from sleeping.


Version-Release number of selected component (if applicable): kernel-2.6.24.3-12.fc8


How reproducible: Always


Steps to Reproduce:
1. Boot Kernel
2. Sit at idle
  
Actual results: ~1600 wakeups


Expected results: ~500 or lower wakeups


Additional info: Attaching lspci, dmesg, and powertop outputs.

This does not happen on my Pentium 4 3ghz HT-enabled 32-bit machine. Same
packages installed.

Comment 1 Michael Cronenworth 2008-03-15 22:47:35 EDT

Created attachment 298174 [details]
dmesg.txt

Comment 2 Michael Cronenworth 2008-03-15 22:48:01 EDT

Created attachment 298175 [details]
lspci.txt

Comment 3 Michael Cronenworth 2008-03-15 22:50:53 EDT

Created attachment 298176 [details]
powertop.txt

Comment 4 Dave Jones 2008-03-15 23:23:22 EDT

it's because of the IR receiver on your TV card.  AFAICT, this is a limitation
of the hardware (it doesn't appear to send an interrupt when it receives an IR
event, so the kernel has to poll frequently to see if something happened).  If
we lower the polling frequency, we may end up missing events.

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