![]() ![]() Obtaining the statistics on your system sudo powermetrics # Displays real-time statistics and system information CPU power measurements are obtained via Intel’s hardware counters (RAPL). I am guessing that at least some of the hardware power measurements come from the SMC chip embedded in the motherboard of Macbook systems. Powermetrics is responsible for collecting data for each process by taking into account diverse factors such as CPU utilization, idle energy draw, network calls, the ability to keep the machine awake or wake it from sleep, disk activity, and combining them into a single reference number for per-process comparison. ![]() OS X is running a service called Powermetrics for all power measurements, and systemstats for process accounting and attribution. An interesting observation is that the graph is quite smooth (seems to use a rolling average of battery charge as the basis, coupled with a large timescale of 12 hours). The graph slopes can provide useful information about current battery health (slopes indicate (dis) / charging rate, which degrades over battery’s life). Bottom-right (blue highlight): This graph displays the battery’s charge availability over time.Remaining charge and time on battery metrics are more reliable and relatively straightforward to obtain (can be read from battery’s inbuilt counters and last charge time respectively). It seems that Apple prefers a risk-free approach by not presenting such a fluctuating number to the majority of end-users. Īlthough Apple does not display the remaining time in the menu bar, the number can still be observed inside this panel. Hence, they removed the remaining time from the menu bar icon. It seems that the system is measuring these attributes for each process as part of the kernel’s process accounting infrastructure ( systemstats).Īpple acknowledges the fact that macOS is not great at determining energy consumption. These attributes can be displayed via right-clicking on the column names at the top. Extra columns (not visible in image): The system also measures additional information per process (CPU Time, CPU %, GPU Time, GPU %, Requires High Perf GPU, Idle Wake Ups, etc).This information is critical as frequent wakeups are well-known to heavily tax the CPU power system, especially in the era of Dark Silicon. Hence, the media player must indicate to the kernel to ignore the sleep timers, for the duration of the playback. On the other hand, if you are watching a movie, even though you are not interacting with the system, you don’t want it to sleep. This happens via automatic timers based on your last interaction with the system (from input devices). This information can also be obtained via pmset -g assertions # Displays current processes preventing system sleepįor example, if you happen to go out for a snack while working, you expect that the system will go to sleep on its own (a feature intended to conserve battery life). Preventing sleep column indicates if the process is preventing the system from sleep. Center-right (green highlight): App Nap column indicates whether the process is currently sleeping (a process can be running on CPU, sleeping, or waiting for I/O, etc.).Here we attempt to break down the information available in the panel: They are simply a unitless reference point, for comparison of energy efficiency among processes.Īpple has noted that since the introduction of these statistics, developers have become vary of code which causes unnecessary high-frequency wake-ups (for example, small animation loops running in the background with frequent updates to display buffers). Further, these numbers are not percentages and will not add up to 100. The energy impact value does NOT indicate the quantitative power consumption (for example, in milliWatts) of the application, akin to PowerTOP. The value ranges from as low as 0 to an indefinite high (the highest value was observed to be around 780 while running the Geekbench stress test ). For comparison, lower numbers are considered better.Īvg Energy Impact: The average energy impact for the past 12 hours or since the system started up, whichever is shorter. Higher energy impact implies a higher load on the system’s battery power consumption.Įnergy Impact: A relative measure of the current power consumption of a process. The tab displays the Energy Impact (red highlight in below image) of each current application (referred to as a process hereafter) based on several factors including CPU usage, network traffic, disk activity, screen brightness, etc. It can be accessed by opening your Activity Monitor (pre-installed on every system) and clicking on the Energy button at the top (Picture shown below). The Energy tab debuted in MAC OS Activity Monitor as part of OS X 10.9 (approximately six years old). ![]()
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