On Wed, Dec 14, 2022 at 8:43 PM Maciej Koszanski <maciejkoszanskibusiness@xxxxxxxxx> wrote: > > Hi Rafael, > > Thank you kindly for your reply! Very much appreciate your time answering my questions. > > Output of /sys/devices/system/cpu/cpu0/cpuidle/state3/desc is ACPI FFH MWAIT 0x60. > Unsure what depth this attribute denotes, but I assume it's either C6/C7. :) Probably C7. > state2/desc is ACPI FFH MWAIT 0x31. I would say C3. > Thank you for the clarification above! I was concerned that as powertop was reporting C3_ACPI, > that the ACPI tables provided C-States with a depth as far as C3, and that Jasper Lake would have > to have it's own static table added for support of deeper states. It is clarified in the intel_idle documentation too, please see: https://www.kernel.org/doc/html/latest/admin-guide/pm/intel_idle.html > I measured the system that I thrown together based on this CPU to pull about 23W from the wall at idle > and 45W under load (with an NVME drive that supports APST, ASPM and L1.2, and 2x 3.5inch HDD's.), > hence the slight obsession to go as low as possible and not be bottlenecked by C-States not going as > deep as they could. That being said, this is a weird, interesting motherboard I sourced from AliExpres > s with minimal documentation. :) > > Many thanks, No problem. Thanks! > On Wed, 14 Dec 2022 at 18:16, Wysocki, Rafael J <rafael.j.wysocki@xxxxxxxxx> wrote: >> >> +Rui who works on intel_idle >> >> Hi, >> >> Please see my responses inline. >> >> On 12/11/2022 10:53 PM, Maciej Koszanski wrote: >> > Dear Rafael, >> > >> > My name is Maciej, and I'm currently using a Jasper Lake chip (Pentium >> > Silver N6005) on an install of Debian as a NAS. I'm reaching out as I >> > believe you're one of the maintainers for the intel_idle kernel, and >> > you authored the related docs for the module, which I found to be a >> > nice read. :) >> > >> Thanks! >> >> >> > I'm currently running Kernel 6.0.0, and while intel_idle successfully >> > loads on Debian (cat /sys/devices/system/cpu/cpuidle/current_driver >> > returns intel_idle), it seems to be defaulting to ACPI c_states >> > (Powertop is reporting C3_ACPI as lowest C-state). >> >> That's correct. >> >> >> > I looked over the source for intel_idle and I don't think there's >> > mention of Jasper Lake, which leads me to believe that it is not >> > supported, I hope I'm not mistaken and that I'm not wasting your time! >> > :) (Tremont-D and Snow Ridge seems to be supported) >> > >> This only means that there is no special idle states table for Jasper >> Lake in intel_idle. The support is based on the C-state tables returned >> by the _CST methods in the ACPI tables of the system which is regarded >> to be sufficient. >> >> As a general rule, special idle states tables are only added for >> processor models where there is a demonstrable advantage from using >> extra C-states or different MWAIT hints with respect to the C-state >> tables from ACPI. >> >> >> > Jasper Lake is starting to gain traction now in mini-PC form factors, >> > and I would greatly appreciate if it was added as a platform in >> > intel_idle to take advantage of the C-states. I'm sorry if the email >> > comes off as if I'm begging for a feature to be implemented, and I'm >> > sure you have other stuff to be busy with, but I greatly appreciate >> > your time in reading this email to this point. :) >> > >> > Attached is an output of my cpuid, from what I gather the chip on the >> > board that I have is capable of going down to C7? >> > >> Yes, it is AFAICS, but the C3_ACPI idle state reported for your platform >> very well may be C7 (please check the MWAIT hint value in the "desc" >> sysfs attribute of the C3_ACPI idle state). >> >> For the future, I would recommend using my kernel.org address (please >> see the CC list of this message) for inquiries regarding the Linux >> kernel and sending CCs of them to linux-acpi@xxxxxxxxxxxxxxx . >> >> Cheers! >> >>
