title: Spring Boot Embedded Tomcat Thread Pool Creation Overhead
body: <p>I am wondering if anyone has information on the performance overhead of adding more threads to a tomcat thread pool?</p>
  
  <p>We have been seeing issues with an app of ours and everything points to an issue with tomcat adding more threads to the thread pool.Is this true? Does adding more threads to the thread pool cause a slowdown in response time?</p>
  
  <p>We are running a Java REST API using Spring Boot and its embedded tomcat. If our problems are indeed caused by tomcat adding more threads to the pool, is there a way to set a minimum in Spring? According to this thread MinSpareThreads does not exist anymore. <a href="https://github.com/spring-projects/spring-boot/issues/3753" rel="nofollow noreferrer">https://github.com/spring-projects/spring-boot/issues/3753</a></p>
  
  <p>If there isn't a way to increase the number of minimum threads with Spring Embedded Tomcat, what are other tools that you use for thread pools?</p>
  
  <p><a href="https://i.stack.imgur.com/gUcup.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/gUcup.png" alt="Thread Increase and Response Time Increase"></a></p>
  
  <p><strong>Edit:</strong>
  I have attached a thread profile. The profile is not of the time in question but later.</p>
  
  <p><a href="https://i.stack.imgur.com/3ppwe.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/3ppwe.png" alt="Thread Profile"></a></p>