I installed i3 once a few years ago, but I had no idea how to use it, so I just closed this thing and got back to Gnome. linux threads created inside a WSL process will be limited to only one processor group.From a long time I wanted to try lightweight WM (Window Manager) for Linux. You can create as many std::threads as you like and not be able to max out the processor usage, and their “parallel STL algorithms” also fail to fully parallelize. LOTs of software lacks the appropriate thread setup code, including: A single socket 64-core AMD threadripper will also have the problem.

My two workstations are a 44-core/88 thread two-socket Xeon system and a 128 core/256 thread AMD system and so I see this all the time. This can be worked around by using SetThreadGroupAffinity to distribute your threads among the available processor groups, or using a library which does so (such as Intel Task Building Blocks).

So, if a system has two sockets or more than 64 HW threads, no matter how many threads you create, it will use half or less of your cores - you’ll see the process monitor’s CPU usage max out at 1/2 (or 1/4) When a thread is created, it is assigned to the processor group of the process that launched it - all processes are assigned a processor group at start. Every thread has an assigned processor group, and will only run on processors in that group.Ī processor group is limited to (a) a max of 64 cores/hardware threads and (b) only HW threads on the same chip for systems with more than one socket (such as dual Xeons). Windows has this thing called a “processor” group.

I3wm for macos