Purpose of this exercise is to simulate a scenario of processing high volumes of "requests" where executed logic is dominated by IO. Two implementations are benchmarked, one using CompletableFutures and another Virtual Threads (Loom).
- program takes two arguments, time interval between each request and duration under test.
- below results are based on 2ms interval between requests and 1 minute duration.
- e.g. with 2ms interval we are simulating 500 requests per second
java -Xss1m -Xmx128m -Xms128m -cp target/vthreads-1.0-SNAPSHOT.jar example.DecisioningCompletableFuture 2 60
java --enable-preview -Xss1m -Xmx128m -Xms128m -cp target/vthreads-1.0-SNAPSHOT.jar example.DecisioningVirtualThreads 2 60
System:
MacBook Pro, Quad-Core Intel Core i7, 2.2 GHz, 4 cores, L2 256KB, L3 6MB, RAM: 16 GB
| Statistic | CompletableFutures | Virtual Threads |
|---|---|---|
| Thread count | 194 | 32 |
| Context switches | 474,675 | 847,098 |
| CPU time | 19.16s | 20.21 |
| Unix calls | 1,381,795 | 1,981,173 |