Code run in a lightweight Virtual Machine can’t take advantage of the Efficiency cores of the host Apple silicon Mac. How then does Sonoma handle its threads?

One of the most distinctive features of Apple silicon chips is that they have two types of CPU core, E (Efficiency) cores that are energy efficient but slower than the P (Performance) cores, which normally run much of the code in the apps we use. Apps don’t decide directly which cores they will be run on, that’s a privilege of macOS, but they register their interest by setting a Quality of Service, or QoS, which is then taken into account when they’re scheduled to run. With the introduction of Game Mode in Sonoma, CPU scheduling can now work differently, with E cores being reserved for the use of games. This article looks at another atypical situation, when running a macOS virtual machine (VM) assigned a set number of virtual cores. How does macOS Sonoma handle that?

  • @abhibeckert
    6•1 year ago

    Just want to point out that this is far from unique to apple

    It’s worth noting that Apple’s partnership with ARM goes back to the 1980’s and included both resources and people all the way back to then (from memory I think the first CEO of ARM was an Apple employee). Your OnePlus 2 has efficiency cores because of Apple’s investment in that architecture.

    But this article is about Macs, not phones. Some Apple Silicon Macs would only last about 2 minutes if they ran on the battery in your OnePlus 2, and the “efficiency cores” aren’t really there to reduce power consumption… it’s more about producing less heat.

    For example the M2 cores are more than capable of running high end PC games, and because they generate almost no heat at all even under full load you can push the GPU much harder than you could if the performance cores were active. Your entire cooling system only needs to keep the GPU cool.

    • @[email protected]English
      3•1 year ago

      I’m consistently impressed with how relatively cool my M2 Air stays when I’m playing No Man’s Sky. I was expecting the game to be throttled to death, but I never see any real performance drops, while still being able to play it on my lap.