The attached patch adds the boolean attribute prestartminSpareThreads to the Executor element. This allows the admin to prestart minspareThreads for this Executor during the start of Tomcat. The default value is false which is the old behaviour. A documentation patch for executor.xml can be created if there is interest in committing this patch.
Created attachment 20996 [details] Patch against 6.0.14
Ping? Any interest? If needed I can provide a patch against 6.0.26.
Nope a patch against trunk would be better.
Created attachment 25291 [details] Patch against Tomcat 6.0 trunk
Created attachment 25292 [details] Patch against Tomcat trunk
This has been implemented in 7.0 at some point (it's documented at http://tomcat.apache.org/tomcat-7.0-doc/config/executor.html).