Add temperature support for M1 Macs

[mikemadden42]

Would it be possible to add temperature support for M1 Macs?

On an Intel Mac, I can use the following to find information about the temperature of system components:

use sysinfo::{System, SystemExt};

fn main() {
    let sys = System::new_all();

    for component in sys.get_components() {
        println!("{:?}", component);
    }
}

PECI CPU: 46.859375°C (max: 0°C)
CPU Proximity: 42.375°C (max: 0°C)
Battery: 30.09375°C (max: 0°C)

On M1 Macs, sys.get_components() appears empty.

$ rustc --version
rustc 1.51.0 (2fd73fabe 2021-03-23)

$ tail -2 Cargo.toml
[dependencies]
sysinfo = "0.16.5"

[mikemadden42]

I wonder if the issue with sysinfo is related to this issue:
iglance/iGlance#225 (comment)

[GuillaumeGomez]

I'd like to add this support but I don't have a mac with M1 processor, so it'll need someone else to implement it. :-/

[nbigaouette]

This Objective-C project seems to be able to read some temperature on the M1: https://github.com/freedomtan/sensors_cmdline/

I'll see if I can hack something...

EDIT: There is also this project (still in Objective-C): https://github.com/fermion-star/apple_sensors

[GuillaumeGomez]

Good luck!

[nbigaouette]

Good luck!

It's dangerous to go alone, I'll get all the luck I can!

:D

[GuillaumeGomez]

On any objective-C related source code, it's very useful indeed. :3

[fdncred]

just adding my voice here in wishing sensors worked on M1. :)

[GuillaumeGomez]

Same answer: I don't have a mac with M1 processors so I'll need someone to do it. :)

[zannis]

I could help with this one if you can provide some info on how to approach it, I'm pretty new to Macs internals :/

[GuillaumeGomez]

You have everything you need in this message. The difficulty being to find the C equivalent of the objective-C API so you can call it from rust.

[macshome]

Yeah, the issue is that the older code is using the SMC to get temperatures and M1 Macs don't have a SMC. They share the sensor layout with iOS devices for things like the CPU. This means you need to talk to IOKit to get the info.

Seeing as this has been sitting like this for a long time, and I've wanted to dabble in Rust, I might take a look at it.

P.S. To call Obj-C from just about anything that talks C you can use the objc_msgSend method. There are some Rust tools built on this as well like rust-objc.

[GuillaumeGomez]

It's in this file.

P.S. To call Obj-C from just about anything that talks C you can use the objc_msgSend method. There are some Rust tools built on this as well like rust-objc.

I removed all objective-C code from sysinfo and I'd prefer to keep it this way. :)

If needed, you can simply reimplement the objective-C function (I can help with that if you don't know how to do it) by looking at its source code.

[macshome]

I installed rust and read some docs last night to take a look at this in more depth. Seems like it's pretty straightforward to get the C working and then define those externals in the ffi class. I've got M1 and M1 Pro MacBooks to test with.

Work is busy, so I'm not blasting through it unfortunately.

[GuillaumeGomez]

It's fine, take your time. And thanks for working on this!

[macshome]

Going through this it seems we can get the temps without resorting to private SPI calls. As a question though, which temperature sensor are most interested in? I assume it's the closest analog to the CPU Proximity (heat spreader) "TC0P" that is being used in the existing code?

[GuillaumeGomez]

You can get all of them, no need to filter. :)

Currently it's not about filtering on mac but more like there isn't a generic way to get all of them (because they have IDs that change at each update for whatever reason...).

[macshome]

Well, a M1 Pro (10-core CPU) has 64 HIDEvent temp sensors it seems. Since the M1 Macs are all SoC based I suppose the differences in distance are minimal.

How would you like to consume the list from my code? Dictionary? Array? I assume you want the name and the temp value for each.

[GuillaumeGomez]

The answer is here (so yes, a vector for the moment, maybe I'll switch to a hash map later on... But out of scope in here).

[macshome]

Here is a list of the sensors and temps on a 10 Core M1 Pro. Some of the names are easier than others to figure out. In your code you seem to be looking at 4 in particular. Is that still the case here or do you just want all of them? It's simple enough to filter or just return them all.

Sensor Name	Temp C
gas gauge battery	23.2
NAND CH0 temp	24.0
PMU tcal	51.9
PMU tdev1	27.6
PMU tdev2	27.5
PMU tdev3	27.7
PMU tdev4	23.0
PMU tdev5	23.4
PMU tdev6	26.9
PMU tdev7	28.4
PMU tdev8	26.9
PMU tdie0	27.8
PMU tdie1	28.1
PMU tdie10	27.7
PMU tdie2	28.1
PMU tdie3	27.9
PMU tdie4	28.2
PMU tdie5	28.1
PMU tdie6	27.9
PMU tdie7	27.9
PMU tdie8	27.9
PMU tdie9	27.9
PMU TP0s	27.8
PMU TP0s	27.8
PMU TP1g	28.1
PMU TP1s	27.5
PMU TP2g	28.1
PMU TP2s	27.7
PMU TP3g	27.6

[GuillaumeGomez]

Like I said, I didn't grow the list because these IDs change between macs and I don't have a generic way to get them all.

In the list you provided, as you long as there is a "readable name" (meaning you'll need a table for this too unfortunately), you can keep all of them.

[macshome]

Ok. That actually makes the ARM sensors easier to get as I’m just asking for all the HID events with the usage page for the internal temperature sensors. The only processing I’ll do is to dedupe and toss the ones without readable names.

I’ll be back to my computers tomorrow and can start looking at how to get this working with the ffi.

[macshome]

OK, taking a look at how to get this working in Rust now. It seems like I add my function prototypes to this ffi.rs file and then implement them in this components.rs file?

[macshome]

I guess the first step is learning how to define and call non-public types and functions in C from Rust. :D

In my main.c I setup the non-public types like this...

#include <IOKit/hidsystem/IOHIDEventSystemClient.h>
#include <stdio.h>

typedef struct __IOHIDEvent *IOHIDEventRef;
typedef double IOHIDFloat;

IOHIDEventSystemClientRef IOHIDEventSystemClientCreate(CFAllocatorRef allocator);
IOHIDEventRef IOHIDServiceClientCopyEvent(IOHIDServiceClientRef, int64_t , int32_t, int64_t);
IOHIDFloat IOHIDEventGetFloatValue(IOHIDEventRef event, int32_t field);

#define kIOHIDEventTypeTemperature  15
#define IOHIDEventFieldBase(type)   (type << 16)

The main sticking point is the import of that specific hidsystem file. I think once I can do that I can declare my types and functions pretty easily. Would copying the header to the project and then using #[link] work?

Sorry to be such a pain on this, this is my first time touching Rust.

[GuillaumeGomez]

No problem, don't worry. We all have to learn somewhere when we begin and your efforts are really appreciated!

OK, taking a look at how to get this working in Rust now. It seems like I add my function prototypes to this ffi.rs file and then implement them in this components.rs file?

Yes and yes.

The main sticking point is the import of that specific hidsystem file. I think once I can do that I can declare my types and functions pretty easily. Would copying the header to the project and then using #[link] work?

It'd be much simpler to simply redeclare them in Rust. For example:

extern "C" {
    pub type IOHIDEventRef = c_void;
    pub type __IOHIDEvent = *mut IOHIDEventRef;

    pub fn IOHIDEventSystemClientCreate(allocator: CFAllocatorRef)-> IOHIDEventSystemClientRef;
}

[macshome]

OK. Been reading up on Rust and finally got my debugger working. Been at horse shows the last two weekends in a row, but hopefully I have some time now to get back to this.

[GuillaumeGomez]

Thanks! Again please remember: we're not in a hurry so take as much time as you want/need.

[GuillaumeGomez]

Fixed in #792.

[macshome]

Thanks for getting this done. I haven't had the time and have had some debates with work about allowing me to participate.

[GuillaumeGomez]

No problem. We were lucky that someone had a mac M1, time and motivation to do it. ;)