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> just as they would on an Intel processor with its identical cores. Whilst its true that all intel macs have identical cores, the latest intel architecture also has Efficiency cores that are different from the performance cores.
https://superuser.com/questions/1677692/what-are-performance...
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On Windows (or Linux) you can get power consumption numbers down to the core using tools like HWMonitor. My CPU is currently using 95W, and my GPU uses 15W. Of course then you have fans, motherboard etc. On server hardware (where software-queriable power meters in the power supply are commonplace) having as much power draw from the fans as from the CPU isn't uncommon.
> power consumption numbers down to the core using tools like HWMonitor. These are just rough estimates and can be wildly inaccurate (just like in the OSX post we're discussing). AFAIK there's no facility for actual measurement. > On server hardware (where software-queriable power meters in the power supply are commonplace) Are you certain these are actual meters and not just estimates done in software?
All motherboards contain sensor chips that can measure the voltages of all power supplies that are used on that board.
All modern CPUs (i.e. all CPUs with variable clock frequency) have internal sensors that measure the currents and the voltages provided by their power supplies. From the currents and the voltages the power consumption is computed. The current and voltage values, together with the temperatures provided by one or more temperature sensors, are used by the algorithms that control the turbo clock frequencies. (The reason why power consumption values are needed by the turbo algorithms is because the chip temperature has a too large inertia, if the clock frequency would be reduced only after the temperature is already too high it would be too late; using the power consumption the future temperature raise can be predicted and the clock frequency can be reduced in advance, avoiding the overshooting of the maximum temperature.)
Some of the values provided by the internal CPU sensors are available in model-specific registers, so the monitoring programs can read them and display the CPU power consumption.
The discrete GPUs from NVIDIA and AMD also have internal sensors that can be read by programs to display the GPU power consumption. The GPUs also use their internal sensors to control their clock frequencies.
Most inaccuracies in reporting the power consumption are due to poor or non-existent documentation of the sensors, which affects especially the AMD CPUs and some of the motherboard sensors. The Intel sensors are usually well documented.
How to read and display the power consumption values provided by the internal CPU sensors can be seen e.g. in the source code of the utility turbostat, which can be found in the source tree of the Linux kernel. (https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/lin...)
Apple should have good internal documentation, which should enable accurate power consumption reporting. They cannot blame an external company which refused to provide adequate documentation for the sensors.
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Yes. But why would they? There's no benefit for them.
A lot of reasons to profile this if you want to advertise battery life. Internally it let's you collect metrics on apps threatening your battery life promises and externally it gives the consumers the ability to accurately blame apps when they get lower than expected battery life. For example they can notice that safari uses less power than chrome or that final cut uses way more power than they expected, etc etc
I don't get it. CPU graphs don't show power usage and they never have; they show how much time, percentually, a CPU was busy executing a certain type of task. You can never get a power estimate from a CPU usage graph at all. Even during normal operation purely on performance cores the clock speed will go up and down as the OS idles or new tasks get spawned. Whatever 10% is in your graph changes depending on the state…
Since Apple have full control over each Mac's hardware, couldn't they within a quite narrow average know how much power is consumed? You also have hardware control chips like the T1/T2 that could help narrow this down even further. I would get it for PC's, but here, it's quite different.
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A lot of reasons to profile this if you want to advertise battery life. Internally it let's you collect metrics on apps threatening your battery life promises and externally it gives the consumers the ability to accurately blame apps when they get lower than expected battery life. For example they can notice that safari uses less power than chrome or that final cut uses way more power than they expected, etc etc
They don't want end users to have access to battery life stats. The took that out a few OS X versions ago. They don't people to say, after the last updated I get 1 hour less battery life, WTF?
But, OTOH, if it's happening in the background while you're already using the computer, then those parts were probably going to be on anyways, so I suppose it's fairly context-dependent.
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> power consumption numbers down to the core using tools like HWMonitor. These are just rough estimates and can be wildly inaccurate (just like in the OSX post we're discussing). AFAIK there's no facility for actual measurement. > On server hardware (where software-queriable power meters in the power supply are commonplace) Are you certain these are actual meters and not just estimates done in software?
Any modern computer has facilities for actual measurements. All motherboards contain sensor chips that can measure the voltages of all power supplies that are used on that board. All modern CPUs (i.e. all CPUs with variable clock frequency) have internal sensors that measure the currents and the voltages provided by their power supplies. From the currents and the voltages the power consumption is computed. The curren…
Turbostat uses RAPL data, as you can see by reading the source code you linked.
I mention this because as far as I'm aware it's impractical to actually measure energy directly. I'm fairly certain that all of these types of systems use estimate models - whether it's in software or firmware.
Earlier quoted context omitted.
Any modern computer has facilities for actual measurements. All motherboards contain sensor chips that can measure the voltages of all power supplies that are used on that board. All modern CPUs (i.e. all CPUs with variable clock frequency) have internal sensors that measure the currents and the voltages provided by their power supplies. From the currents and the voltages the power consumption is computed. The curren…
I don't believe this is correct. My understanding is that these tools all use RAPL, and RAPL data is calculated as I suggested (estimates from activity counters) rather than metering amps and volts. Turbostat uses RAPL data, as you can see by reading the source code you linked. I mention this because as far as I'm aware it's impractical to actually measure energy directly. I'm fairly certain that all of these types o…
It's similar on CPUs, but the monitoring circuitry is internal, I think.
I don't get it. CPU graphs don't show power usage and they never have; they show how much time, percentually, a CPU was busy executing a certain type of task. You can never get a power estimate from a CPU usage graph at all. Even during normal operation purely on performance cores the clock speed will go up and down as the OS idles or new tasks get spawned. Whatever 10% is in your graph changes depending on the state…
Yes, but you could (or should) get one from Activity Monitor's energy usage graph (under the "Energy" tab).