I/O-bound endpoint (/io, Thread.sleep(300)), concurrency=600, 2 vCPU sandbox, Spring Boot 4.1.1 / JDK 25.0.4.1
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platform threads : total=600 success=600 wall=1325ms p50=733ms p99=1201ms
virtual threads  : total=600 success=600 wall=1042ms p50=658ms p99=720ms

default embedded Tomcat platform-thread pool = 200; with 600 concurrent 300ms-sleep
requests, platform threads must queue in ~3 sequential batches, virtual threads do not.