I've an application under tomcat. When only a one or two users works on it everithing is ok. When the number of users grows the application slows down. Is not a memory nor a cpu problem : using top I see the system resources quite free. I don't see relevant garbage collection : heap size and permgen have correct dimentions. No other applications are running on the system. I log more or less every relevant operation in my system (db query and so on) and I see that every slowdown is concentered in a single operation. I mean all operations take "normal" time but one or two of them take 4 seconds more. The "slowing" operations are not the same in different executions, and theydo not have a specific type (not only DB query, not only DB stored procedures, not only.....). It seems like if the thread is frozen for a fixed amount fo time (4 seconds more or less) and then it restarts. I don't think it's a "queue" problem because otherwise the wait time would be unperdictable and not a "fixed" 4 seconds time. I don't know any parameter impacting on that behaviour. I use Tomcat 7.0.32 with JVM 1.7.0.67 on a Linux server. Could someone suggest a solution for my problem or, at least, an investigation strategy. Tks
Tullio
