Hello again, my answers to questions: 1. It is the latest Debian on Raspberry Pi (aka Raspbian). Hardware is Raspberry Pi. 2. Maybe "idle" is not the best word in my case. Yes, app is deployed on server but it is just for this: wait for incoming data over POST and the save it to database. No traffic currently. (so it should not do anything else) Tomcat is 7. Apache Tomcat/7.0.28, JVM 1.7.0_25-b30 3. Profiler - I am newbie, but I will try to google it and run it.
I see always at least 3.9% CPU in top. 2015-02-24 16:34 GMT+01:00 David kerber <dcker...@verizon.net>: > On 2/24/2015 10:16 AM, Christopher Schultz wrote: > >> -----BEGIN PGP SIGNED MESSAGE----- >> Hash: SHA256 >> >> Daniel, >> >> On 2/24/15 8:01 AM, Daniel Mikusa wrote: >> >>> On Tue, Feb 24, 2015 at 7:33 AM, Peter Irbizon >>> <peterirbi...@gmail.com> wrote: >>> >>> Hello, I would like to know if it is normal that tomcat7 runs on >>>> 3.9% CPU when idle? I saw all other processes are at 0%, only >>>> tomcat7 is always at least 3.9%. >>>> >>>> >>> 1.) What's your system like? How many CPUs / cores? Is it a VM or >>> hardware? What is the specific version of Tomcat? of Java? What >>> OS are you running? >>> >>> 2.) How are you determining it's idle? As John mention, do you >>> have any apps deployed? Do you know if traffic is hitting the >>> server? >>> >>> 3.) Can you run a profiler and attach it to Tomcat? It'll tell >>> you what's happening inside the JVM. >>> >> >> 4. Take a few thread dumps to see what the JVM threads are doing. >> >> When truly idle (i.e. no requests are being processed), Tomcat runs a >> maintenance thread that performs some background tasks, but that runs >> about once every 60 seconds and does very little, depending on what >> you have configured. >> >> So unless you are seeing that thread specifically running at its >> interval, Tomcat's threads are totally blocked waiting on various >> events to occur (like an I/O event for an incoming request, or waiting >> for a timeout to perform that maintenance). >> >> On a dev server, I just checked and my Tomcat processes go down to 0.0 >> CPU as measured by top when they aren't "doing" anything. >> > > There is also the question of "3.9% of what"? If it's a slow, single core > machine, it's a lot more likely that TC might use 3% of it, than it is if > it's a 16-core 3.5GHz server. > > > >> The thread dumps will likely tell the story. >> >> - -chris >> > > > > --------------------------------------------------------------------- > To unsubscribe, e-mail: users-unsubscr...@tomcat.apache.org > For additional commands, e-mail: users-h...@tomcat.apache.org > >
