Linux 6.11 Merges Intel P-State Patch For Emerald Rapids To Yield Better Performance

[phoronix]

Phoronix: Linux 6.11 Merges Intel P-State Patch For Emerald Rapids To Yield Better Performance

Last week I wrote about 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...

https://www.phoronix.com/news/Linux-6.11-Lands-EMR-EPP-Update

[emansom]

Is RAPL supposed to work fine on Zen 4? Is there any guidance on how to interpret the values? Is it microjoule/second? microjoule/hour?

On my Zen 4 7600 it reports as the following:

10:49 root@am5ws ~# cat /sys/devices/virtual/powercap/intel-rapl/intel-rapl:0/energy_uj              
6741987308
10:49 root@am5ws ~# cat /sys/devices/virtual/powercap/intel-rapl/intel-rapl:0/intel-rapl:0:0/energy_uj
267744423

[aviallon]

Is RAPL supposed to work fine on Zen 4? Is there any guidance on how to interpret the values? Is it microjoule/second? microjoule/hour?

On my Zen 4 7600 it reports as the following:

10:49 root@am5ws ~# cat /sys/devices/virtual/powercap/intel-rapl/intel-rapl:0/energy_uj
6741987308
10:49 root@am5ws ~# cat /sys/devices/virtual/powercap/intel-rapl/intel-rapl:0/intel-rapl:0:0/energy_uj
267744423

It is microjoule, period.
You are supposed to compute the delta over each second to get the power consumption.