r/java • u/jaccomoc • 22h ago

Vert.x Event-Loop vs Virtual Threads: Jactl Suspend/Resume Benchmark

https://jactl.io/blog/2026/09/02/jactl-virtual-threads-benchmark

The article benchmarks Jactl script execution with differing number of blocking operations comparing throughput with Jactl built-in suspend/resume on Vert.x Event-Loops and throughput with Jactl on Virtual Threads. The benchmarks are run on both Java 21 and Java 25 with some surprising (to me at least) results.

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u/s0ftware-dev 21h ago

TLDR virtual threads are better. 

-5

u/jaccomoc 21h ago

But only on Java 25 and not by as much as I thought they would be.

I was frankly surprised at the difference between Java 21 and Java 25.

8

u/Joram2 20h ago

Even at similar speeds, the Vert.x event loop has a much higher complexity cost. I've used vert.x for years, it's great, a lot of the vert.x platform has value with virtual threads, but the future for most use cases is clearly virtual threads.

2

u/jaccomoc 20h ago

I agree completely. It wins alone just by removing all the async code handling we used to have to do.