Re: when idle tomcat runs on 3.9% CPU
Am 27.02.2015 um 18:07 schrieb Christopher Schultz:
-BEGIN PGP SIGNED MESSAGE-
Hash: SHA256
Peter,
On 2/27/15 11:21 AM, Peter Irbizon wrote:
Hi Chris, here are my dumps
http://www.filedropper.com/jvmthreaddump. It looks like it has
something to do with memcached.
There are a bunch of RUNNABLE threads, but sometimes the term
RUNNABLE in a Java thread dump doesn't actually mean taking CPU
time right now. For example, the main thread is RUNNABLE but it's
waiting on accepting a socket connection (for a SHUTDOWN command) and
so it's effectively blocked, taking zero CPU time.
I'm not entirely sure what the Memcached threads actually do, but I
think they are in a similar situation: waiting for code to request
some communication with Memcached.
I agree, hard to say from those dumps what's consuming the CPU, could be
even GC threads. It's easier if threads are actually doing something,
not just hanging around and waiting for work.
If you have commandline access, use
top -H -p PID
to show the list of threads of your process (replace PID by the process
ID of your Java process) and check, what the thread numbers that are
active on the CPU are. Hopefully it is only a few threads. Then take the
thread number and translate it from decimal to hexadecimal and look for
it in the header lines of your thread dumps.
Example:
The thread
Memcached IO over {MemcachedConnection to localhost/127.0.0.1:11215}
prio=10 tid=0x025558d8 nid=0x34d3 runnable [0x9f4fe000]
from the dump will be shown on some Linuxes in top -H as thread id
0x34d3 = 13523
on others as
0x025558d8 = 39147736
If the thread ID doesn't occur in the thread dump at all, then it is
native threads (unlikely but possible).
Regards,
Rainer
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Re: when idle tomcat runs on 3.9% CPU
-BEGIN PGP SIGNED MESSAGE- Hash: SHA256 Peter, On 2/27/15 11:21 AM, Peter Irbizon wrote: Hi Chris, here are my dumps http://www.filedropper.com/jvmthreaddump. It looks like it has something to do with memcached. There are a bunch of RUNNABLE threads, but sometimes the term RUNNABLE in a Java thread dump doesn't actually mean taking CPU time right now. For example, the main thread is RUNNABLE but it's waiting on accepting a socket connection (for a SHUTDOWN command) and so it's effectively blocked, taking zero CPU time. I'm not entirely sure what the Memcached threads actually do, but I think they are in a similar situation: waiting for code to request some communication with Memcached. - -chris 2015-02-27 16:46 GMT+01:00 Christopher Schultz ch...@christopherschultz.net : Peter, On 2/27/15 10:41 AM, Peter Irbizon wrote: 2015-02-27 16:32 GMT+02:00 Christopher Schultz ch...@christopherschultz.net : How much memory is in this thing? I have one with 700 MHz ARM1176JZ, 512MB RAM (model B). By the way it is working pretty nice :) I tried just to figure it out why only tomcat7 consumes some CPU when all other services are at 0%. Can you get a shell running on it? If so, take thread dumps of the JVM process: that will tell you (or us) what's going on. You can adjust the background thread's timing, but it's pretty innocuous. -chris - To unsubscribe, e-mail: users-unsubscr...@tomcat.apache.org For additional commands, e-mail: users-h...@tomcat.apache.org -BEGIN PGP SIGNATURE- Version: GnuPG v1 Comment: GPGTools - http://gpgtools.org iQIcBAEBCAAGBQJU8KRjAAoJEBzwKT+lPKRY41QP/1/pu4TGNkXTx82g08vWG/zL nGccJgD9+G2sM2YGR17l6XcCwlZ28LfGwSid6Ub3lezLXMwl6Au4fRt8smdMv9jO 7tEO/naBxbIDLW3wtzwN1ttpgoF9TPsfk8XGuCYLeAq/p+qC9yEyl/OC5yP0ybnj bAVBB41KHx5FVT/+GxyIBArSxE+7DxbCLpLPndr2jLxJvJKh4AbXWEOmNpAoJpHH owi0iWKYbRf/ApADWarblCpflqob1mlkUNQRrz/ZEfbfgaYsQute7Qcz0xLtjT00 Z+gP9NjqWufZL9jIl9gI7IWs93e9oWK283LNHj52qHMtSonq9jx3h0OTCoCICGEq w4mAErC1Hm8r9N069mo4XtJinnTGGNwC71a9akpKqyIQM7K500bDLze9+RvayVVr Cbv8aOQMrvvM0no7Q8KGqgkm6KU1rp4bYFqAbOMzb57AE+lU7LCl/MUzxjCl75Ip qm2i5NnW78NMRmeYpfD6p4ViEzRM7eaguUUyb1hSSD/g/tJM2VNeZ7BiXn+50VXF RcsC5pmHw/mwW8aW2PN8IjwghzAX2TxI6EX37B1TCp8T4vEg8fjKxJ9cwr62UwHJ 35ObBalDumZlstGoRfPhpBHMJW8xnzKkWC0QWP5SQy0ZSDIad0Vvc1mMvEMn27n8 FFp0n7tv/mE5URaTjd8J =i1lo -END PGP SIGNATURE- - To unsubscribe, e-mail: users-unsubscr...@tomcat.apache.org For additional commands, e-mail: users-h...@tomcat.apache.org
Re: when idle tomcat runs on 3.9% CPU
-BEGIN PGP SIGNED MESSAGE- Hash: SHA256 Chuck, On 2/27/15 9:14 AM, Caldarale, Charles R wrote: From: Peter Irbizon [mailto:peterirbi...@gmail.com] Subject: Re: when idle tomcat runs on 3.9% CPU 1. It is the latest Debian on Raspberry Pi (aka Raspbian). Hardware is Raspberry Pi. That would seem to fit Chris' postulation pretty much exactly: It was David's postulation, but honestly... I'm impressed that someone got Tomcat running on a Raspberry Pi. When I think Raspberry Pi, I must admit that Java isn't the first solution that comes to mind. How much memory is in this thing? - -chris -BEGIN PGP SIGNATURE- Version: GnuPG v1 Comment: GPGTools - http://gpgtools.org iQIcBAEBCAAGBQJU8IAOAAoJEBzwKT+lPKRYlhoP/1m1e1t5k9zJ0JeeyxZPn0tF fY96sD9wTvbXcOGQyFh36roAdHSONkljc3JSmxEc/mBNowwRXBv1vAWYUexYwEal Pbm7wblwpyIstTpJnV++RtoikIbSHmhXGi7CeVccCfIO0Exj+n4amXVMrztl8C8Z Q5WEU1GJloUZffsCnTtqO51ivpX9FPuZxcpwbbxMhjhn2cBqrbfe7QlBWEKirTB7 zXazRMcWElwN8XUVtc1tZgq4qaSo7MDKZXvYTcnF2vz5HzNPiUZYAFF9TNdjk9mY 0CjKDQofuebuWopkXo30c6BvY4eY3OLrzLTjDait4mIM75Y7F5/Snku/979kJMSx povLrQK19ZDTaibIRIXpbxmWArFUw6+Ty/XcDIo4NPX8y0bRXa04VePVD4fSTHII t1vPrfFeMresQck42iqVhKoT/PaSVHIztAVNRMe6BF4g6mVK4D0IfMpVQ/m951Oy TIJoFrbOlh5G0nzC5P6+Bc4UA3ovh+RETRUjNYwSv/YGgrxLAhiXH7KcjzAHnAcD i6OoEc1k+xGZ8Xga7+5GrK23T94rvmR+fAow7UiYCM9P1UFRk/RCPkDsE5LMxYUE sTi0QFFu4yA9BZHJEZM6myjXqF6RNyo5eDF32oB+4jaMcQ/nvLd5gbKCrjGAveQ6 PINQyLCGmoNUb+DPC8bC =G3ec -END PGP SIGNATURE- - To unsubscribe, e-mail: users-unsubscr...@tomcat.apache.org For additional commands, e-mail: users-h...@tomcat.apache.org
RE: when idle tomcat runs on 3.9% CPU
From: Peter Irbizon [mailto:peterirbi...@gmail.com] Subject: Re: when idle tomcat runs on 3.9% CPU 1. It is the latest Debian on Raspberry Pi (aka Raspbian). Hardware is Raspberry Pi. That would seem to fit Chris' postulation pretty much exactly: 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. - Chuck THIS COMMUNICATION MAY CONTAIN CONFIDENTIAL AND/OR OTHERWISE PROPRIETARY MATERIAL and is thus for use only by the intended recipient. If you received this in error, please contact the sender and delete the e-mail and its attachments from all computers. - To unsubscribe, e-mail: users-unsubscr...@tomcat.apache.org For additional commands, e-mail: users-h...@tomcat.apache.org
Re: when idle tomcat runs on 3.9% CPU
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
Re: when idle tomcat runs on 3.9% CPU
2015-02-27 16:32 GMT+02:00 Christopher Schultz ch...@christopherschultz.net: How much memory is in this thing? It varies, 256MB or 512MB for model B, if I remember it right. Have one serving DHCP at home :) - To unsubscribe, e-mail: users-unsubscr...@tomcat.apache.org For additional commands, e-mail: users-h...@tomcat.apache.org
Re: when idle tomcat runs on 3.9% CPU
On 2/27/2015 9:14 AM, Caldarale, Charles R wrote: From: Peter Irbizon [mailto:peterirbi...@gmail.com] Subject: Re: when idle tomcat runs on 3.9% CPU 1. It is the latest Debian on Raspberry Pi (aka Raspbian). Hardware is Raspberry Pi. That would seem to fit Chris' postulation pretty much exactly: 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. Yup. That's probably what the background listening threads take on that hardware and OS combination. Also consider that the OS probably hasn't had the amount of optimization on RP that it has on desktop or server hardware. - To unsubscribe, e-mail: users-unsubscr...@tomcat.apache.org For additional commands, e-mail: users-h...@tomcat.apache.org
Re: when idle tomcat runs on 3.9% CPU
2015-02-27 16:32 GMT+02:00 Christopher Schultz ch...@christopherschultz.net : How much memory is in this thing? I have one with 700 MHz ARM1176JZ, 512MB RAM (model B). By the way it is working pretty nice :) I tried just to figure it out why only tomcat7 consumes some CPU when all other services are at 0%.
Re: when idle tomcat runs on 3.9% CPU
-BEGIN PGP SIGNED MESSAGE- Hash: SHA256 Peter, On 2/27/15 10:41 AM, Peter Irbizon wrote: 2015-02-27 16:32 GMT+02:00 Christopher Schultz ch...@christopherschultz.net : How much memory is in this thing? I have one with 700 MHz ARM1176JZ, 512MB RAM (model B). By the way it is working pretty nice :) I tried just to figure it out why only tomcat7 consumes some CPU when all other services are at 0%. Can you get a shell running on it? If so, take thread dumps of the JVM process: that will tell you (or us) what's going on. You can adjust the background thread's timing, but it's pretty innocuous. - -chris -BEGIN PGP SIGNATURE- Version: GnuPG v1 Comment: GPGTools - http://gpgtools.org iQIcBAEBCAAGBQJU8JFyAAoJEBzwKT+lPKRY9SMP/RV6RlUThwVDqRngMto/vPn9 3iwgANTuK7WKCV0RCVFbLoC17+GL4h7fCEl18GTwKSJf0k76MsrYPhrVQrgzTstd ylDK0gPYgLVWHwmBKJjMsi/KYlKdfNjPeSgVqALrzJXk/gNHrrVOandRnYXePRN/ JGfk/6/KeXvWRk3nvOsx2VfVsKKeghBj4ED9l52E/EvOxhXcMQBHPJHs5vWPa3GA jqIL1DUID/Q1dx3G3hthXROLAmHZVXPqD+tZ7Z1NjTFPJPc9+s8Rg8+tnqwph5fG osPuq3Qx4XXVSbYzuGoFxH+DdiR4LEP+KU7H/3TuhR5tTV4dEzgU93KYJsszUkCw eofe1XTPZj+dgmzAMircBbi8M5aeaRFHqC8s8V/Rbk8KJ84TDKqP0TzBh0N08by5 bAr9vCGOO9t9+Sbs+RdZCAHDoJz0UKKERWP++NxpeRVtYc5G07eeBdQBGVJ0Rk7I WPvyrzBsr225RBiDyBf8/xDWLqgSA+Rn6TX2g+U5R0+fw3ssnQfzqRRUfeyckpth wvvWCMn2neT/KtqqUIBVTV9q/OMgeHVjo7bY7iI6vo+k22Q4zoaxeGJ7g3OQwA0p 8xeTZ4jvsGmLz2U6der2fmXAn8K1y40oxM1gR2Yocm9Z7p19XLGquU4m2QTJ655L rx3sGgP20Y2OsTlMiQMV =poQC -END PGP SIGNATURE- - To unsubscribe, e-mail: users-unsubscr...@tomcat.apache.org For additional commands, e-mail: users-h...@tomcat.apache.org
Re: when idle tomcat runs on 3.9% CPU
Hi Chris, here are my dumps http://www.filedropper.com/jvmthreaddump. It looks like it has something to do with memcached. 2015-02-27 16:46 GMT+01:00 Christopher Schultz ch...@christopherschultz.net : -BEGIN PGP SIGNED MESSAGE- Hash: SHA256 Peter, On 2/27/15 10:41 AM, Peter Irbizon wrote: 2015-02-27 16:32 GMT+02:00 Christopher Schultz ch...@christopherschultz.net : How much memory is in this thing? I have one with 700 MHz ARM1176JZ, 512MB RAM (model B). By the way it is working pretty nice :) I tried just to figure it out why only tomcat7 consumes some CPU when all other services are at 0%. Can you get a shell running on it? If so, take thread dumps of the JVM process: that will tell you (or us) what's going on. You can adjust the background thread's timing, but it's pretty innocuous. - -chris -BEGIN PGP SIGNATURE- Version: GnuPG v1 Comment: GPGTools - http://gpgtools.org iQIcBAEBCAAGBQJU8JFyAAoJEBzwKT+lPKRY9SMP/RV6RlUThwVDqRngMto/vPn9 3iwgANTuK7WKCV0RCVFbLoC17+GL4h7fCEl18GTwKSJf0k76MsrYPhrVQrgzTstd ylDK0gPYgLVWHwmBKJjMsi/KYlKdfNjPeSgVqALrzJXk/gNHrrVOandRnYXePRN/ JGfk/6/KeXvWRk3nvOsx2VfVsKKeghBj4ED9l52E/EvOxhXcMQBHPJHs5vWPa3GA jqIL1DUID/Q1dx3G3hthXROLAmHZVXPqD+tZ7Z1NjTFPJPc9+s8Rg8+tnqwph5fG osPuq3Qx4XXVSbYzuGoFxH+DdiR4LEP+KU7H/3TuhR5tTV4dEzgU93KYJsszUkCw eofe1XTPZj+dgmzAMircBbi8M5aeaRFHqC8s8V/Rbk8KJ84TDKqP0TzBh0N08by5 bAr9vCGOO9t9+Sbs+RdZCAHDoJz0UKKERWP++NxpeRVtYc5G07eeBdQBGVJ0Rk7I WPvyrzBsr225RBiDyBf8/xDWLqgSA+Rn6TX2g+U5R0+fw3ssnQfzqRRUfeyckpth wvvWCMn2neT/KtqqUIBVTV9q/OMgeHVjo7bY7iI6vo+k22Q4zoaxeGJ7g3OQwA0p 8xeTZ4jvsGmLz2U6der2fmXAn8K1y40oxM1gR2Yocm9Z7p19XLGquU4m2QTJ655L rx3sGgP20Y2OsTlMiQMV =poQC -END PGP SIGNATURE- - To unsubscribe, e-mail: users-unsubscr...@tomcat.apache.org For additional commands, e-mail: users-h...@tomcat.apache.org
Re: when idle tomcat runs on 3.9% CPU
When you say idle, is there an application deployed to tomcat, or is it just the bare app server with nothing deployed? On Tue Feb 24 2015 at 7:35:31 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%.
when idle tomcat runs on 3.9% CPU
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%.
Re: when idle tomcat runs on 3.9% CPU
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. Dan
Re: when idle tomcat runs on 3.9% CPU
-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. The thread dumps will likely tell the story. - -chris -BEGIN PGP SIGNATURE- Version: GnuPG v1 Comment: GPGTools - http://gpgtools.org iQIcBAEBCAAGBQJU7JXcAAoJEBzwKT+lPKRYbpoP/iEYzgNjKkAXyvo907sJe6vY 0gVe3qLlZiuQGQLnlXHxTOTP701+IxK+3TzQN6jO2+dCNAZkJvup+xOzRLUavHk2 fNMYUgsPdCugg9S64Vfx7Mmo7Id9zX9UZ49yg+cwWAp7OAYaGfB6QIY/ux6C0zxB /ELOjGvyE1gHrenhovtVptze4JBBOzpsa2AMl1bnz4mtfVk5p8+21VI7u5e3gfRU 4lE5tNsjekWXnxUVwg4FNzDuIY2KP2Wqq7sNE6QSKhoIltuT+DB0g8u71ARQzkJH atMNuu7lG0auZqUQRhUxtCJ/6DIshHNxKlhCT91AjF9Mc3rdNSadTd7/j3DslCcL 0TnhdznXPou5LJgYNmdW4AVD6FQqxEf+0JW7o8jq4bbJ3NYlDVjhFoFMskN7IsOD h6uDzvS3nLrYuKJjsBNQWBRloMNtiy/fIa37AZeXrl81CubSgDPO3kYJs3fzjs9j srLvGEoctaHHA8N6ZWI+PL4r2vgLhu5iRY4Hh6OHHQ8zpnzKO1vWbqw0oFD44TQ6 tnuPyEwclm44tdAonAxmAyRLxpACVdjBp2hMbZq8YvcetCi/XvuRs3nhp5NpIZnE QHxEk2BpCGWoQxGTkLuEtj+vf/EwqAUyk+qLXV04lo29KcO4maxh4HYYViM/rSgb rC5Fm3UhC3vhkxwRE8/e =Wts6 -END PGP SIGNATURE- - To unsubscribe, e-mail: users-unsubscr...@tomcat.apache.org For additional commands, e-mail: users-h...@tomcat.apache.org
Re: when idle tomcat runs on 3.9% CPU
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
