AMD Linux Driver Patch Improves Steam Deck Performance in EPP Mode

As the Steam Deck slowly marches toward its fifth birthday next February, owners are likely eager for a way to extend its life rather than investing in expensive high-end competition. A new patch for AMD’s Linux drivers could substantially reduce low-end frame hitches when the Steam Deck or other AMD-based gaming hardware is running in Energy Performance Preference (EPP) mode. Writing on the Linux kernel mailing list (thanks, Phoronix), kernel coder David Vernet lays out the basic problem that games often face in EPP mode. When a busy thread frequently goes to sleep for short periods, the current AMD driver can misinterpret that behavior as a signal to lower its average performance target. When those threads wake up, they start at a lower-than-desired frequency, leading to increased frame latency, stale frames, and longer frame generation times at the low end of the distribution. Shifting the processor to “performance” mode fixes this problem but eliminates the energy savings that EPP mode is supposed to provide. And simply boosting the affected thread’s minimum performance target permanently actually makes low-end performance worse, thanks to the complexities of CPU/GPU boost management. Vernet’s patch instead monitors cores to look for situations where a busy thread would benefit from an improved clock rate. The patch then temporarily sets just that core to the “performance” setting until the workload slows enough to downshift back into energy-saving EPP mode. The nitty-gritty implementation at a kernel level gets pretty complicated—read through Vernet’s write-up for all the details. But the worst-case performance improvements seem clear in early testing. Vernet’s testing on Civilization VI benchmarks saw a 31.8 percent improvement in the “1% low” fps measurement, and 4.1 percent faster p99 frame generation times (i.e., the point where 99 percent of frames are generated at least that quickly). While this EPP adjustment doesn’t affect the average FPS measurements in Vernet’s benchmark, speeding up the slowest frames the game generates should help moderate the occasional jerky frame hitches that can occur when running a game in EPP mode. We’ll likely have to wait for Vernet’s submitted patch to be integrated into the full AMD Linux kernel to see how the new feature fares on other common gaming benchmarks. Regardless, it’s nice to see that low-level Linux coding updates are still wringing some performance improvements from Valve’s quickly aging handheld hardware.