Trying to implement basic concurrent code with actors

Using Swift
, ,
9

This simple executable takes about 8.6s (in debug and release mode) to create and execute 50,000 tasks in a group. Little actual CPU usage during that time, so it seems just enqueuing the work takes a while.

import CoreFoundation

@main
struct ConcurrencyTest {
    static func main() async {
        let start = CFAbsoluteTimeGetCurrent()
        await withTaskGroup(of: Void.self) { group in
            @Sendable
            func doNothing() {}
            
            for _ in 0..<50_000 {
                group.addTask {
                    doNothing()
                }
            }
            
            await group.waitForAll()
        }
        print(CFAbsoluteTimeGetCurrent() - start)
    }
}

While running it only used five threads, so there must be other considerations for execution width than just number of cores (this is an i9 iMac with 10/20 cores).