CONFIG_NR_CPUS=256 is too low
Affects | Status | Importance | Assigned to | Milestone | |
---|---|---|---|---|---|
linux (Ubuntu) |
Fix Released
|
Medium
|
Tim Gardner | ||
Xenial |
Fix Released
|
Undecided
|
Unassigned | ||
Yakkety |
Fix Released
|
Medium
|
Tim Gardner |
Bug Description
Intel Knights Landing systems boot up to 272 processor cores. The stock Ubuntu Linux kernel images leave processor cores above 256 disabled:
[ 0.000000] ACPI: NR_CPUS/
[ 0.000000] ACPI: NR_CPUS/
[ 0.000000] ACPI: NR_CPUS/
[ 0.000000] ACPI: NR_CPUS/
[ 0.000000] ACPI: NR_CPUS/
[ 0.000000] ACPI: NR_CPUS/
[ 0.000000] ACPI: NR_CPUS/
[ 0.000000] ACPI: NR_CPUS/
[ 0.000000] ACPI: NR_CPUS/
[ 0.000000] ACPI: NR_CPUS/
[ 0.000000] ACPI: NR_CPUS/
[ 0.000000] ACPI: NR_CPUS/
[ 0.000000] ACPI: NR_CPUS/
[ 0.000000] ACPI: NR_CPUS/
[ 0.000000] ACPI: NR_CPUS/
[ 0.000000] ACPI: NR_CPUS/
I'd request an increase in CONFIG_NR_CPUS to 512. This would match Debian's default setting. For comparison, RHEL/CentOS ship with 4096.
affects: | linux-meta (Ubuntu) → linux (Ubuntu) |
Changed in linux (Ubuntu): | |
importance: | Undecided → Medium |
tags: | added: kernel-da-key |
Changed in linux (Ubuntu Yakkety): | |
status: | Confirmed → Fix Committed |
Changed in linux (Ubuntu Xenial): | |
status: | New → Fix Committed |
tags: |
added: verification-done-yakkety removed: verification-needed-yakkety |
Changed in linux (Ubuntu): | |
status: | Fix Committed → Fix Released |
Status changed to 'Confirmed' because the bug affects multiple users.