On Thu, Sep 26, 2024, at 2:14 PM, Mario Limonciello wrote: > On 9/26/2024 08:58, Mark Pearson wrote: >> Thanks Mario, >> >> On Wed, Sep 25, 2024, at 10:59 PM, Mario Limonciello wrote: >>> From: Mario Limonciello <mario.limonciello@xxxxxxx> >>> >>> There are two major ways to tune platform performance in Linux: >>> * ACPI platform profile >>> * Manually tuning APU performance >>> >>> Changing the ACPI platform profile is a "one stop shop" to change >>> performance limits and fan curves all at the same time. >>> >>> On AMD systems the manual tuning methods typically involve changing >>> values of settings such as fPPT, sPPT or SPL. >>> >>> The problem with changing these settings manually is that the definition >>> of the ACPI platform profile if supported by the hardware is no longer >>> accurate. At best this can cause misrepresenting the state of the >>> platform to userspace and at worst can cause the state machine into an >>> invalid state. >>> >>> The existence and continued development of projects such as ryzenadj which >>> manipulate debugging interfaces show there is a demand for manually tuning >>> performance. >>> >>> Furthermore some systems (such as ASUS and Lenovo handhelds) offer an >>> ACPI-WMI interface for changing these settings. If using anything outside >>> that WMI interface the state will be wrong. If using that WMI interface >>> the platform profile will be wrong. >>> >>> This series introduces a "custom" ACPI platform profile and adds support >>> for the AMD PMF driver to use it when a user has enabled manual >>> adjustments. >>> >>> If agreeable a similar change should be made to asus-armoury and any other >>> drivers that export the ability to change these settings but also a >>> platform profile. >>> >> >> As someone who supports customers on Lenovo devices and hits the occasional situation where a user has made strange tweaks to different power related settings, and then complains about power or thermal issues - I love the idea that it can be made clear the system has been 'adjusted' in a non standard way. I can also see why users would want interfaces to do those changes. > > JFYI we're going to do something really similar in amdgpu when people > have enabled overclocking. That's part of the inspiration for this RFC. > > https://lore.kernel.org/amd-gfx/CADnq5_M+vxGV6y8oEQHC+-CcqV-vW9ND4SsRHqHKbwR_b0iJ9g@xxxxxxxxxxxxxx/T/#m1d69399c3e799ea1ef2014a27fd6e555f9e70ba0 > Nice :) >> >> Some suggestions: >> >> I'm wondering if we can make it so a driver can register only a 'custom' profile as an extra profile handler? >> >> The thinking here is the custom setting in this series is implemented for the amd sps driver, and therefore on a regular Lenovo laptop wouldn't be used, as the thinkpad_acpi driver will grab the profile slot, Users on Lenovo systems aren't going to be able to get at these extra tweaks (unless they unload thinkpad_acpi, which has other side effects). > > Well the RFC was just to show it for the AMD PMF driver, but I think > that thinkpad_acpi, asus_armoury etc could all potentially implement the > 'custom' bit too if they offer an ACPI-WMI interface to similar settings. > >> >> If the sps driver can offer a custom mode, separately from thinkpad_acpi, then users can tweak settings to their hearts content but get back to regular mode when done. >> >> I also think there needs to be a way that when you switch from custom back to a 'regular' profile that it would do a clean up of anything tweaked. e.g. when switching away from custom the ppd driver should call a 'custom mode cleanup' function, so things can be undone and returned to how they were when it was started. >> >> Mark > > I guess what you're proposing is that multiple drivers register as > profile handlers and they might not all export the same features. > > If we did something like this we could instead have the core call > callbacks for all platform profile handlers. We could also drop a pile > of quirks from amd-pmf where there are some ASUS systems that advertise > SPS in in the PMF framework and also asus-wmi provides it. > > If I'm following you right, I generally like this idea. Yep - that was the idea. This feels like a step towards giving more control to power users - whilst keeping the basic simple for regular folk. I can imagine utilities that would use this to enable specific configurations, via the custom profile mode, for many different scenario's; whilst still allowing a user to get back to the tested and vendor approved setting if things go badly. Mark
