Bug 588702 - v7 incorrectly uses 'processor.can_throttle' to plan CPUSCALING tests
v7 incorrectly uses 'processor.can_throttle' to plan CPUSCALING tests
Status: CLOSED ERRATA
Product: Red Hat Hardware Certification Program
Classification: Red Hat
Component: Test Suite (tests) (Show other bugs)
1.1
All Linux
low Severity medium
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Assigned To: Greg Nichols
CAI Qian
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Depends On:
Blocks:
  Show dependency treegraph
 
Reported: 2010-05-04 06:37 EDT by Gary Smith
Modified: 2010-10-23 11:12 EDT (History)
6 users (show)

See Also:
Fixed In Version:
Doc Type: Bug Fix
Doc Text:
The CPU scaling test now checks the content of /sys/devices/system/cpu/cpu<n>/cpufreq/scaling_available_frequencies file.
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Last Closed: 2010-09-20 08:14:13 EDT
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Attachments (Terms of Use)
cpuscaling test patch to check /sys/../cpu<n>/cpufreq/scaling_available_frequencies for test planning (999 bytes, patch)
2010-07-28 13:44 EDT, Greg Nichols
no flags Details | Diff

  None (edit)
Description Gary Smith 2010-05-04 06:37:43 EDT
The v7 cert suite uses the info “processor.can_throttle = true (bool)” to find out if the CPUs are scalable. This is incorrect because:

throttling (T states)

..are different to:

cpu_scaling (C states)

In some old documents it seems to be the same, but there’s now a mandatory difference between both states.

A system can offer “cpu_scaling”, but must not offer “throttling”. It depends what is implemented in the BIOS.

It is being 'assumed' (but not yet proven) that this is the reason that 'v7 plan' never automatically adds CPUSCALING tests to the plan on Fujitsu hardware.


Actual results:
v7 does not automatically add CPUSCALING tests for each core on Fujitsu hardware


Expected results:
v7 should automatically add CPUSCALING tests for each core on Fujitsu hardware
Comment 1 Bob Sanders 2010-06-29 12:01:59 EDT
We're seeing the same issue at SGI.  With Intel 5600 cpus and AMI bios, 
cpuscaling is not turned on by v7.  But with the same cpus and an Intel
bios cpu scaling is automatically selected.

Bob
Comment 3 Greg Nichols 2010-07-28 13:44:25 EDT
Created attachment 435093 [details]
cpuscaling test patch to check /sys/../cpu<n>/cpufreq/scaling_available_frequencies for test planning
Comment 9 errata-xmlrpc 2010-09-20 08:14:13 EDT
An advisory has been issued which should help the problem
described in this bug report. This report is therefore being
closed with a resolution of ERRATA. For more information
on therefore solution and/or where to find the updated files,
please follow the link below. You may reopen this bug report
if the solution does not work for you.

http://rhn.redhat.com/errata/RHBA-2010-0702.html
Comment 10 Jaromir Hradilek 2010-09-21 08:52:51 EDT
    Technical note added. If any revisions are required, please edit the "Technical Notes" field
    accordingly. All revisions will be proofread by the Engineering Content Services team.
    
    New Contents:
The CPU scaling test now checks the content of /sys/devices/system/cpu/cpu<n>/cpufreq/scaling_available_frequencies file.

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