clj-virtual-threads

An experiment with Java21 Virtual Threads and Clojure. Both examples just update an atom counter over 100000 threads, comparing the execution time between a virtual thread and a "real" thread.

Disclaimer

This was a very quick thought experiment but there are some issues. Take these numbers with a grain of salt See this hacker news thread

Running

Using the Clojure CLI, you can run this program like so:

clj src/main.clj

Results

M3 Mac

count:  100000
virtual start time (ms):  1722446540075
virtual end time (ms):  1722446540306
virtual elapsed time (ms):  231
count:  100000
real start time (ms):  1722446540311
real end time (ms):  1722446543667
real elapsed time (ms):  3356

Intel Mac

count:  100000
virtual start time (ms):  1722449512852
virtual end time (ms):  1722449513318
virtual elapsed time (ms):  466
count:  100000
real start time (ms):  1722449513330
real end time (ms):  1722449520618
real elapsed time (ms):  7288