My iPhone is behaving slowly, so I am trying to watch CPU usage in Instruments.app on a Mac to see if any particular process is to blame. But the CPU activity in the "Activity Monitor" instrument doesn't make sense to me. Right now it's showing a steady CPU Total Load ranging between 30% to 40%. But in the list of processes below, they add up to less than 1% in the %CPU column. So what is actually being measured at 30% and is there a better way I should be diagnosing this?

  • Is there an objective measure of slow? 5 seconds to launch an app? What hardware and is the battery new? On intel and arm chips, when the system throttles, cpu frequency dips, so activity monitor and instruments won’t help. – bmike Mar 2 '18 at 3:00

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