Bug 825400 - Hyperthreading not working on i7-3770S
Summary: Hyperthreading not working on i7-3770S
Keywords:
Status: CLOSED NOTABUG
Alias: None
Product: Fedora
Classification: Fedora
Component: kernel
Version: 17
Hardware: x86_64
OS: Linux
unspecified
high
Target Milestone: ---
Assignee: Kernel Maintainer List
QA Contact: Fedora Extras Quality Assurance
URL:
Whiteboard:
Depends On:
Blocks:
TreeView+ depends on / blocked
 
Reported: 2012-05-25 23:01 UTC by Kevin Clevenger
Modified: 2012-05-29 14:22 UTC (History)
5 users (show)

Fixed In Version:
Clone Of:
Environment:
Last Closed: 2012-05-29 14:22:49 UTC
Type: Bug
Embargoed:

Attachments (Terms of Use)
sosreport (808.41 KB, application/octet-stream)
2012-05-25 23:01 UTC, Kevin Clevenger 		no flags Details
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Description Kevin Clevenger 2012-05-25 23:01:40 UTC 
Created attachment 586965 [details]
sosreport

Description of problem:
F17 with current updates on a Biostar TZ77B with an i7-3770S shows only 4 cores. 

Version-Release number of selected component (if applicable):
3.3.7-1.fc17.x86_64

How reproducible:
Boot and check /proc/cpuinfo

Steps to Reproduce:
1. N/A
2.
3.

Actual results:
CPU's 0-3 are available

Expected results:
CPU's 0-7 should be available

Additional info:
I have tested the identical setup and BIOS settings with another distro and hyperthreading works correctly when running it.
Comment 1 Dave Jones 2012-05-27 21:19:42 UTC 
you booted with acpi=off, forcing the kernel to fall back to using the legacy MPS method of cpu enumeration, which it seems is broken on your BIOS.

Turn acpi back on, and it should be fine.
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