3 ms·

So, like nice[1], except the developer sets the level of importance ahead of time? Makes sense, as long as I can reprioritize if needed. 1. https://en.wikipedi

So, like nice[1], except the developer sets the level of importance ahead of time? Makes sense, as long as I can reprioritize if needed. 1. https://en.wikipedia.org/wiki/Nice_(Unix) https://en.wikipedia.org/wiki/Nice_(Unix)

bombcar 5y ago
It's nice but with additional limitations - on a normal Unix system even if you nice everything to the lowest level possible they'll still take over all cores. This limits things below a certain nice level to the efficiency cores, meaning that the performance cores are always available for foreground action.
- damagednoob 5y ago
  So nice + taskset[1]? 1: https://linux.die.net/man/1/taskset https://linux.die.net/man/1/taskset
  - archi42 5y ago
    Seems so. Just that it works "automagically" and reserves some cores for certain priority groups. Maybe one can write a script/daemon that `taskset`s all tasks with a certain niceness range (or by additional rules) to a few "background cores" and everything else to the "interactive cores"? On Linux you might also get some problems with kworker threads landing in the wrong group, but I'm not that much into Kernel internals I've to admit.
    - jamespo 5y ago
      Could do it with SystemD AllowedCPUs functionality, but that's not dynamic
    - wmf 5y ago
      These days you'd probably want to use cpuset cgroups so you don't have to worry about individual processes.
- ape4 5y ago
  Of course the applications (programmers of the applications) need to declare their "nice" levels correctly - they can't be greedy
- stefan_ 5y ago
  Nothing has ever stopped Apple from pinning indexing work to specific cores. They just didn't give a shit.
  - bombcar 5y ago
    I suspect they did it less for performance and more for energy savings - this prevents the scheduler from moving a background process to a performance core (which a naive one would do if it saw the performance core underutilized).
  - astrange 5y ago
    It's always done this but the effect wasn't visible on x86.
ytch 5y ago
Maybe like the big.little cores of many ARM CPU in Android phone? I'm not familiar with Android APP, maybe there are similar APIs in Android?
- agloeregrets 5y ago
  It's the same big.Little concept, slightly tweaked to allow this QoS work, I believe most of it was then used on Android but I doubt that Android uses the APIs well if they exist.

bombcar 5y ago

It's nice but with additional limitations - on a normal Unix system even if you nice everything to the lowest level possible they'll still take over all cores. This limits things below a certain nice level to the efficiency cores, meaning that the performance cores are always available for foreground action.

damagednoob 5y ago
So nice + taskset[1]? 1: https://linux.die.net/man/1/taskset https://linux.die.net/man/1/taskset
- archi42 5y ago
  Seems so. Just that it works "automagically" and reserves some cores for certain priority groups. Maybe one can write a script/daemon that `taskset`s all tasks with a certain niceness range (or by additional rules) to a few "background cores" and everything else to the "interactive cores"? On Linux you might also get some problems with kworker threads landing in the wrong group, but I'm not that much into Kernel internals I've to admit.
  - jamespo 5y ago
    Could do it with SystemD AllowedCPUs functionality, but that's not dynamic
  - wmf 5y ago
    These days you'd probably want to use cpuset cgroups so you don't have to worry about individual processes.
ape4 5y ago
Of course the applications (programmers of the applications) need to declare their "nice" levels correctly - they can't be greedy
stefan_ 5y ago
Nothing has ever stopped Apple from pinning indexing work to specific cores. They just didn't give a shit.
- bombcar 5y ago
  I suspect they did it less for performance and more for energy savings - this prevents the scheduler from moving a background process to a performance core (which a naive one would do if it saw the performance core underutilized).
- astrange 5y ago
  It's always done this but the effect wasn't visible on x86.

ytch 5y ago

Maybe like the big.little cores of many ARM CPU in Android phone? I'm not familiar with Android APP, maybe there are similar APIs in Android?

agloeregrets 5y ago
It's the same big.Little concept, slightly tweaked to allow this QoS work, I believe most of it was then used on Android but I doubt that Android uses the APIs well if they exist.