lettuce-nioEventLoop thread is comsuming lot of CPU after migrating to spring boot 3.1.2

[sumit-kumar-iitm]

We were running an application with spring boot 2.4.3 with Java8, recently we migrated to Spring boot 3.1.2 and Java17.
After migration we started seeing lettuce-nioEventLoop-#-# in our new relic which is taking up a lot of system CPU time. Prior to migration it was not even there on the new-relic dashboard.
Any suggestions what could have gone wrong. It is just the dependency change

[mikebell90]

So I wonder if it's the changes in Java 17 and 21 that will expose more CPUs to a containerized app? Are you running one? Java 8 also had a back and forth I believe, but you. might be running an older one that works more like the original behavior

[mikebell90]

If so, try adding -XX:+UseContainerCpuShares to the JVM temporarily to see if the old behavior works. And display the EXACT jvm version (not just 17, which isn't enough)

[tishun]

@sumit-kumar-iitm did you try this suggestion? Did it work?

[sumit-kumar-iitm]

We have reverted the upgrade as of now but I will try your suggestion and update on this thread. But for your reference I am sharing the most system time-consuming threads graph. You can see after we reverted lettuce-nio-EventLoop thread is negligible