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Bug #10514

10277 broke older Intel CPUs

Added by Robert Mustacchi 4 months ago. Updated 4 months ago.

Status:
Closed
Priority:
Normal
Category:
kernel
Start date:
2019-03-08
Due date:
% Done:

100%

Estimated time:
Difficulty:
Medium
Tags:

Description

The changes in 10277 were not quite correct and on older Intel CPUs without CPUID leaf 0xb, such systems fail to boot. The problem is that the logic in cpuid_intel_ncores() is incorrect. While we correctly source the number of cores via leaf 4, we incorrectly assigned the number of threads based on the number sharing the smallest cache. This is basically never correct.

Instead, this needs to be obtained the same way it was in the past, via cpuid leaf 1.


Related issues

Related to illumos gate - Feature #10277: Properly detect SMT on AMDClosed2019-01-24

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History

#1

Updated by Electric Monk 4 months ago

  • Status changed from New to Closed

git commit d6517bbd3d5d20a36c32ac87627207632e5934aa

commit  d6517bbd3d5d20a36c32ac87627207632e5934aa
Author: Robert Mustacchi <rm@joyent.com>
Date:   2019-03-12T15:31:31.000Z

    10514 10277 broke older Intel CPUs
    10513 Regression in westmere MCA initialization
    Reviewed by: Jerry Jelinek <jerry.jelinek@joyent.com>
    Reviewed by: John Levon <john.levon@joyent.com>
    Reviewed by: Peter Tribble <peter.tribble@gmail.com>
    Approved by: Dan McDonald <danmcd@joyent.com>

#2

Updated by Marcel Telka 4 months ago

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