[bug] [BDX]Ubuntu 16.04.3 with kernel "4.10.0-32-generic_4.10.0-32.36~16.04.1_amd64" hang if set "Cores Enabled" to 2 for both CPU
Bug #1747134 reported by
quanxian
This bug affects 1 person
Affects | Status | Importance | Assigned to | Milestone | |
---|---|---|---|---|---|
linux (Ubuntu) |
Fix Released
|
Medium
|
Canonical Kernel Team | ||
Xenial |
Incomplete
|
Medium
|
Unassigned | ||
Artful |
Won't Fix
|
Medium
|
Unassigned | ||
Bionic |
Fix Released
|
Medium
|
Canonical Kernel Team |
Bug Description
Description:
Customer report a Ubuntu kernel issue related to Intel BDX Core numbers setting
Ubuntu 16.04.3 with kernel "4.10.0-
We have reproduced this issue on 17.10 release.
With latest kernel, this issue disappears.
now we bisect this issue is fixed by commit 947134d9b00f (“x86/smpboot: Do not use smp_num_siblings in __max_logical_
But after applying this commit to Ubuntu 16.04.3 kernel v4.13 code base or Linux upstream mainline kernel v4.13 code base, this issue still exists.
Target Release: 16.04 / 17.10
tags: | added: kernel |
information type: | Proprietary → Public |
Changed in linux (Ubuntu Artful): | |
status: | New → Triaged |
Changed in linux (Ubuntu Bionic): | |
status: | New → Triaged |
Changed in linux (Ubuntu Artful): | |
importance: | Undecided → Medium |
Changed in linux (Ubuntu Bionic): | |
importance: | Undecided → Medium |
Changed in linux (Ubuntu Artful): | |
assignee: | nobody → Canonical Kernel Team (canonical-kernel-team) |
Changed in linux (Ubuntu Bionic): | |
assignee: | nobody → Canonical Kernel Team (canonical-kernel-team) |
tags: | added: bionic |
tags: | added: kernel-da-key |
Changed in linux (Ubuntu Xenial): | |
status: | New → Triaged |
importance: | Undecided → Medium |
assignee: | nobody → Joseph Salisbury (jsalisbury) |
Changed in linux (Ubuntu Artful): | |
assignee: | Canonical Kernel Team (canonical-kernel-team) → Joseph Salisbury (jsalisbury) |
Changed in linux (Ubuntu Artful): | |
status: | Triaged → In Progress |
Changed in linux (Ubuntu Xenial): | |
status: | Triaged → In Progress |
Changed in linux (Ubuntu Xenial): | |
status: | In Progress → Incomplete |
no longer affects: | intel |
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Correct the fix commit info. But applying this patch to v4.13, the issue still exists. It may have more dependencies.
commit 947134d9b00f342 415af7eddd42a5f ce7262a1b9
Author: Prarit Bhargava <email address hidden>
Date: Mon Dec 4 11:45:21 2017 -0500
x86/smpboot: Do not use smp_num_siblings in __max_logical_ packages calculation
Documentati on/x86/ topology. txt defines smp_num_siblings as "The number of
threads in a core". Since commit bbb65d2d365e ("x86: use cpuid vector 0xb
when available for detecting cpu topology") smp_num_siblings is the
maximum number of threads in a core. If Simultaneous MultiThreading
(SMT) is disabled on a system, smp_num_siblings is 2 and not 1 as
expected.
Use topology_ max_smt_ threads( ), which contains the active numer of threads, packages calculation.
in the __max_logical_
On a single socket, single core, single thread system __max_smt_threads has packages calculation happens, so its
not been updated when the __max_logical_
zero which makes the package estimate fail. Initialize it to one, which is
the minimum number of threads on a core.
[ tglx: Folded the __max_smt_threads fix in ]
Fixes: b4c0a7326f5d ("x86/smpboot: Fix __max_logical_ packages estimate")
Reported-by: Jakub Kicinski <email address hidden>
Signed-off-by: Prarit Bhargava <<email address hidden>
Signed-off-by: Thomas Gleixner <email address hidden>
Tested-by: Jakub Kicinski <email address hidden>