** Changed in: linux (Ubuntu Kinetic)
Status: In Progress => Won't Fix
** Changed in: linux (Ubuntu Jammy)
Status: In Progress => Fix Committed
** Changed in: linux (Ubuntu Lunar)
Status: In Progress => Fix Committed
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https://bugs.launchpad.net/bugs/2008745
Title:
[SRU] Intel Sapphire Rapids HBM support needs CONFIG_NUMA_EMU
Status in linux package in Ubuntu:
In Progress
Status in linux source package in Jammy:
Fix Committed
Status in linux source package in Kinetic:
Won't Fix
Status in linux source package in Lunar:
Fix Committed
Bug description:
[Impact]
Currently Ubuntu kernel has this kernel config disabled.
But in some cases, Intel's Sapphire Rapids High Bandwith
Memory (SPR-HBM) needs this option.
Memory bandwidth has been a bottleneck of increasingly memory bound
workloads. Sapphire Rapids plus HBM is specifically targeted to
cater to these workloads, traditionally served using overprovisioning
of memory devices.
Please search the keyword "fake numa" in
https://community.intel.com/t5/Blogs/Products-and-
Solutions/HPC/Enabling-High-Bandwidth-Memory-for-HPC-and-AI-
Applications-for/post/1335100
[Fix]
Enable CONFIG_NUMA_EMU in our kernel config for 5.15 and later
[Test Plan]
Use "STREAM-triadd" algorithm* in Intel MLC** to benchmark 3 scenarios (no
fake NUMA, 2U fake NUMA and 4U fake NUMA).
*
https://www.intel.com/content/www/us/en/developer/articles/technical/optimizing-memory-bandwidth-on-stream-triad.html
**
https://www.intel.com/content/www/us/en/download/736633/intel-memory-latency-checker-intel-mlc.html
An improvement to performance on a Sapphire Rapids CPU with HBM should
be observed
[Where problems could occur]
The regression risk is low
[Other Info]
Jammy
https://code.launchpad.net/~mreed8855/ubuntu/+source/linux/+git/jammy/+ref/lp_2008745_config_numa_emu_2
Kinetic
https://code.launchpad.net/~mreed8855/ubuntu/+source/linux/+git/kinetic/+ref/lp_2008745_config_numa_emu_kinetic
Lunar
https://code.launchpad.net/~mreed8855/ubuntu/+source/linux/+git/lunar/+ref/config_numa_emu_lunar_2
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