Intel Preparing The Linux Kernel For Cascade Lake AP Multi-Die Support

Written by Michael Larabel in Intel on 19 February 2019 at 03:44 PM EST. 4 Comments
Intel developers have begun posting their Linux kernel patches for enabling multi-die/package topology support to the Linux kernel as part of their Cascade Lake AP upbringing.

Cascade Lake "Advanced Performance" is a multi-chip package of multiple Cascade Lake dies, expected to be up to 48 cores / 96 threads per package and twelve DDR4 memory channels. Cascade Lake SP and Cascade Lake X Linux support already has been in order -- or at least appears to be based upon previous commit activity -- while Cascade Lake AP is taking some additional work due to the new multi-die design. Cascade Lake dies are connected via Ultra Path Interconnect (UPI) links.

Sent out on Monday were 11 patches for the initial multi-die/package support, in order for the kernel to discover the multi-die/package topology, export the topology inside the kernel and to user-space via sysfs, and update the various bits of the kernel to differentiate between per-die and per-package machine specific registers (MSRs).

Hitting the mailing list today were the perf subsystem patches for handling the multi-die design of Cascade Lake AP.

Cascade Lake AP will also require updates to TurboStat, lscpu, and other user-space utilities though that work hasn't been submitted yet for review.

In going through these patches so far, no new details on Cascade Lake AP were revealed -- just prepping for the multi-chip package groundwork. If the patches are accepted promptly, this work could still appear in the upcoming Linux 5.1 merge window.
Related News
About The Author
Michael Larabel

Michael Larabel is the principal author of and founded the site in 2004 with a focus on enriching the Linux hardware experience. Michael has written more than 20,000 articles covering the state of Linux hardware support, Linux performance, graphics drivers, and other topics. Michael is also the lead developer of the Phoronix Test Suite, Phoromatic, and automated benchmarking software. He can be followed via Twitter, LinkedIn, or contacted via

Popular News This Week