Last week I wrote about [1]a tiny Linux patch yielding up to 32% faster performance and up to 18% less energy for Emerald Rapids CPUs . That patch is an adjustment to the Intel P-State driver's Energy Performance Preference (EPP) value for that Intel Xeon Scalable family. Today that patch was merged for the Linux 6.11 kernel.

That patch adjusts the Intel Xeon Emerald Rapids EPP value for the P-State driver when running in the "balance_performance" mode such as is the default on Ubuntu Linux. Canonical engineers found adjusting this value could make the POV-Ray ray-tracer run 32% faster with 12% less energy, OpenSSL up to 12% faster, or the kernel compilation 29% faster while using 18% less energy.

These are some nice wins for Emerald Rapids though unfortunate it came now considering that Emerald Rapids has been shipping since the end of last year. It's also matching the EPP value already set in the driver for prior Sapphire Rapids processors.

In any event today's [2]power management update for Linux 6.11 has merged this Emerald Rapids "balance performance" EPP update. It's now in Linux Git and part of Sunday's Linux 6.11-rc3 release.

Sadly, not making this power management pull request for Linux 6.11 is still [3]this patch needed for getting Zen 5 power consumption monitoring working under Linux. There's also still [4]this patch to fix power reporting for multi-CCD AMD CPUs as a regression since Linux 6.9. Hopefully those will still manage to make it into Linux 6.11.



[1] https://www.phoronix.com/news/One-Line-Linux-Faster-Intel-EMR

[2] https://lore.kernel.org/lkml/CAJZ5v0hQ3O7E3ygvFKbzjkJbx7pddyD9Qc+rE4EFYzJS12oTMg@mail.gmail.com/

[3] https://lore.kernel.org/linux-pm/20240719101234.50827-1-Dhananjay.Ugwekar@amd.com/

[4] https://lore.kernel.org/linux-pm/20240730044917.4680-1-Dhananjay.Ugwekar@amd.com/T/#m7a59207d34b40a54971193b75d36c14dafee7824