Following the various Intel graphics driver feature updates sent out earlier this week in building up the new kernel graphics/display driver features for Linux 6.15, another prominent pull request was sent out yesterday with additional material.
The latest Intel pull request for the Intel kernel driver code is the main drm-intel-gt-next update for Linux 6.15. Most notable there for end-users is now allowing GuC power profile adjustments via sysfs. Via sysfs the GuC SLPC power profile can be adjusted for those aiming for more power efficient behavior of their Intel graphics hardware.
The GuC’s Single Loop Power Control (SLPC) manages the GT frequency based on how busy it is and how it’s initialized by the kernel driver. Power profiles some control over the SLPC and in turn the GT frequency.
The GuC SLPC power profile behavior has two modes: its default “base” profile or a “power saving” profile mode. With that power saving mode, the SLPC resorts to more conservative thresholds for ramping the GT frequency and in turn can help save power. In the power saving mode, the Intel kernel graphics driver will also disable waitboosts as another power savings advantage.
For those trying for more power efficient performance, “power_saving” can be written to the new “slpc_power_profile” sysfs file as an alternative to the “base” default.
That addition is part of this Intel GT pull request ahead of the upcoming Linux 6.15 merge window. It will be interesting to see in practice how much power savings this GuC SLPC adjustment can provide with no insight into the power savings as part of the patch.
The pull additionally has a new performance optimization for Intel “Gen12” Tigerlake and Alder Lake graphics by setting “WAIT_ON_DEPTH_STALL_DONE_DISABLE” for fast clear flushes. Details in this tracking ticket.
