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Bug 1517839 - stale cpu frequency in /proc/cpuinfo
Summary: stale cpu frequency in /proc/cpuinfo
Status: CLOSED DUPLICATE of bug 1511701
Alias: None
Product: Fedora
Classification: Fedora
Component: kernel
Version: 27
Hardware: Unspecified
OS: Unspecified
Target Milestone: ---
Assignee: Kernel Maintainer List
QA Contact: Fedora Extras Quality Assurance
Depends On:
TreeView+ depends on / blocked
Reported: 2017-11-27 15:07 UTC by Dalibor Pospíšil
Modified: 2017-11-27 17:48 UTC (History)
19 users (show)

Fixed In Version:
Doc Type: If docs needed, set a value
Doc Text:
Clone Of:
Last Closed: 2017-11-27 17:48:29 UTC

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Description Dalibor Pospíšil 2017-11-27 15:07:46 UTC
Description of problem:
CPU frequency in /proc/cpuinfo is not the actual one. The is regression against kernel-4.13.12-200.fc26.x86_64

Version-Release number of selected component (if applicable):

How reproducible:

Steps to Reproduce:
1. grep 'cpu MHz' /proc/cpuinfo
2. cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_cur_freq 

Actual results:
the first gives stale numbers
while the second reflect reality

Expected results:
both should correspond

Comment 1 Dalibor Pospíšil 2017-11-27 15:51:16 UTC
I had this issue also prior the kernel-4.13.12-200.fc26.x86_64 on few kernels, this was somehow fixed in kernel-4.13.12-200.fc26.x86_64 and broken again in kernel-4.13.13-200.fc26.x86_64

Comment 2 Jeremy Cline 2017-11-27 17:48:29 UTC

Thank you for the bug report. This is a known issue. A fix landed in 4.13.12, but was reverted for 4.14 and 4.13.13 as it performs poorly on systems with many cores. A new fix is being worked on.

*** This bug has been marked as a duplicate of bug 1511701 ***

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