Intel's One Line Of Linux Code For Speeding-Up Sapphire Rapids On Ubuntu
This round of tests were on the Intel Xeon Platinum 8490H server with Ubuntu 23.04 while using a Linux 6.2 kernel build, Linux 6.3 where this patch was mainlined, and also doing a run with Linux 6.3 in the performance governor mode rather than powersave for still showing the power/performance difference on the table.
Right off the bat with workloads that tend to be sensitive to CPU frequency scaling driver/governor changes, there is a huge boost confirmed by the Linux 6.3 kernel usage... (And for those using stock Ubuntu kernels, this patch is back-ported to their shipped kernels.)
The Linux 6.3 performance with the default P-State powersave governor is much better than found on mainline Linux 6.2 and nearly to the performance seen by using the performance governor.
There is a significant uplift to the out-of-the-box performance for Sapphire Rapids for those using the powersave governor rather than performance.
This does mean increased power usage compared to the old P-State behavior, but for most of the benchmarks was ultimately delivering better power efficiency than the prior default behavior.
The OpenJDK Java workloads also tend to be sensitive to the CPU frequency scaling behavior.