Intel P-State Changes Could Improve iGPU-Bound Performance - Some Cases ~15%, ~43% Perf-Per-Watt

We've known that Intel's P-State Linux CPU frequency scaling driver in general can be a bit quirky and especially so when dealing with Intel integrated graphics where the iGPU and CPU share the same power envelope. This has been shown with examples like using the "powersave" governor to boost iGPU performance while discrete graphics owners are generally best off switching over to the "performance" governor. As the latest though on helping the iGPU front with P-State, there is a new patch series talking up big gains in performance and power efficiency.

Francisco Jerez of Intel's open-source driver team sent out a set of ten patches today working on GPU-bound efficiency improvements for the Intel P-State driver.

By tuning P-State to yield better CPU energy efficiency in TDP-limited scenarios, on an Icelake-based Razer Blade Stealth with integrated graphics, the raw graphics performance improved by about 15% while the performance-per-Watt as measured by the RAPL framework improved by around 43%. Note though the impact of these patches may differ depending upon your particular Intel CPU and its integrated graphics.

The tentative patches improving P-State can be found on the mailing list. Hopefully the work will be well received if the enhancements really live up to expectations and will make it to a mainline kernel this year.