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From "Cammy Ng" <ca...@businetcomm.com>
Subject Re: [REPOST]: mod_jk: ajp13: cpu load problem with apache
Date Fri, 17 May 2002 18:53:24 GMT
Hi,

I am sorry that I don't understand what you mean about a loop hole??, my
setting is apache on machine1, first tomcat on machine2, second tomcat on
machine3, mod_jk ajp13 is install on apache to do the load balancing. After
certain time on running, apache will use up 100% CPU time, if I just stop
and start apache, the cpu load will back to 2% with the same amount of user.

Thanks

----- Original Message -----
From: "Vaneet Sharma" <Vaneet@iwg.info>
To: "'Tomcat Users List'" <tomcat-user@jakarta.apache.org>
Sent: Friday, May 17, 2002 2:50 AM
Subject: RE: [REPOST]: mod_jk: ajp13: cpu load problem with apache


> I would suggest you to recheck the Tomcat-Apache installation procedure ..
> search on internet the right procedure...
>   i think there is a loop hole while installing
> man
>    if possible do again
>     and see
>      chao
> vaneet
>
> -----Original Message-----
> From: Cammy Ng [mailto:cammy@businetcomm.com]
> Sent: 17 May 2002 07:16
> To: Tomcat Users List
> Subject: Re: [REPOST]: mod_jk: ajp13: cpu load problem with apache
>
>
> Hi,
>
> I have exactly problem you have. Hope anyone can solve this problem.
>
> Thanks
>
> ----- Original Message -----
> From: "Costas Stergiou" <csterg@aias.gr>
> To: "Tomcat Users List" <tomcat-user@jakarta.apache.org>
> Sent: Wednesday, May 15, 2002 10:14 PM
> Subject: [REPOST]: mod_jk: ajp13: cpu load problem with apache
>
>
> > Hi all,
> > nobody seemed to reply anything on this matter. Looking through
> > the code myself I came to some conclusions but actually the one(s)
> > who really know the code should take a look.
> >
> > PLEASE, take another look at this problem. Actually, the Apache-Tomcat
> > integration is useless with such a problem (and there are no
alternatives
> > if you want load balancing...). I know that others have reported similar
> > issues.
> >
> > Any help???
> >
> > Thanks,
> > Costas
> >
> > > Hi Costin,
> > > continuing on the problem:
> > >
> > > 1. I downloaded the latest code from CVS and compiled mod_jk.
> > > 2. Run apache with it and used gdb to get a stack trace upon
> > > the problem. Here is the gdb output:
> > >
> > > [helium]/#gdb httpd 24550
> > > GNU gdb 5.0-aix43-010414
> > > Copyright 2000 Free Software Foundation, Inc.
> > > GDB is free software, covered by the GNU General Public License, and
you
> > are
> > > welcome to change it and/or distribute copies of it under certain
> > > conditions.
> > > Type "show copying" to see the conditions.
> > > There is absolutely no warranty for GDB.  Type "show warranty" for
> > details.
> > > This GDB was configured as "powerpc-ibm-aix4.3.3.0"...httpd: No such
> file
> > or
> > > dir
> > > ectory.
> > >
> > > //24550: No such file or directory.
> > > Attaching to process 24550
> > > (no debugging symbols found)...(no debugging symbols found)...
> > > (no debugging symbols found)...(no debugging symbols found)...
> > > (no debugging symbols found)...(no debugging symbols found)...
> > > (no debugging symbols found)...(no debugging symbols found)...
> > > (no debugging symbols found)...(no debugging symbols found)...
> > > (no debugging symbols found)...(no debugging symbols found)...
> > > (no debugging symbols found)...(no debugging symbols found)...
> > > (no debugging symbols found)...(no debugging symbols found)...
> > > (no debugging symbols found)...(no debugging symbols found)...
> > > (no debugging symbols found)...(no debugging symbols found)...
> > > (no debugging symbols found)...(no debugging symbols found)...
> > > (no debugging symbols found)...(no debugging symbols found)...
> > > (no debugging symbols found)...(no debugging symbols found)...
> > > (no debugging symbols found)...(no debugging symbols found)...
> > > (no debugging symbols found)...(no debugging symbols found)...
> > > (no debugging symbols found)...(no debugging symbols found)...
> > > ---Type <return> to continue, or q <return> to quit---
> > > [Switching to Thread 1]
> > > 0x20070e9c in jk_tcp_socket_recvfull ()
> > > (gdb) bt
> > > #0  0x20070e9c in jk_tcp_socket_recvfull ()
> > > #1  0x2006b700 in ajp_connection_tcp_get_message ()
> > > #2  0x200694c0 in ajp_get_reply ()
> > > #3  0x20069344 in ajp_service ()
> > > #4  0x200744c8 in jk_handler ()
> > > #5  0x10020900 in ap_invoke_handler ()
> > > #6  0x10044c30 in process_request_internal ()
> > > #7  0x10045db4 in ap_process_request ()
> > > #8  0x10002a50 in child_main ()
> > > #9  0x1000244c in make_child ()
> > > #10 0x10002140 in perform_idle_server_maintenance ()
> > > #11 0x10001aec in standalone_main ()
> > > #12 0x10001390 in main ()
> > > #13 0x100001dc in __start ()
> > > (gdb) quit
> > > A debugging session is active.
> > > Do you still want to close the debugger?(y or n) y
> > > Detaching from program: , process 24550
> > >
> > > The only way to stop the above is either by restarting apache or
> > > killing the runaway apche process. gdb reports the same until I kill
> > > the process (never gets out of that process).
> > > Also, I must note that at the same time the jvm tomcat process also
> > > consumes a lot of CPU untill I kill the httpd process.
> > > Also, I use tomcat 4.0.3 with the compiled java mod_jk libs that
> > > come with the distribution.
> > >
> > > I hope that you can give some feedback on the above.
> > > Also, I think that the above problem is occurring when I press
> > > the stop button on my browser while I have made a 'big' request (one
> > > that brings back a 'big' html page).
> > >
> > > Any help is greatly welcome,
> > > Thanks,
> > > Costas
> > >
> > >
> > >
> > > ----- Original Message -----
> > > From: <costinm@covalent.net>
> > > To: "Tomcat Users List" <tomcat-user@jakarta.apache.org>
> > > Sent: Thursday, May 02, 2002 7:57 PM
> > > Subject: Re: Re: mod_jk: ajp13: cpu load problem with apache
> > >
> > >
> > > > On Thu, 2 May 2002 csterg@aias.gr wrote:
> > > >
> > > > > First of all thank you for your interest.
> > > > > I will download the latest code and try this out. I do have the
> debug
> > > mode
> > > > > enabled so I will sent you any errors (although I have not noticed
> > > anything
> > > > > special).
> > > > > I don't think though that I can reproduce the problem myself.
> > > > > About the gdb, I have no experience of how to attach to the
process
> > but
> > > I will
> > > > > do my best to find a colleague that does.
> > > >
> > > > Short course on gdb:
> > > >
> > > > ps -aux |grep httpd
> > > > ( or ps -fea )
> > > >
> > > > Find the PID of the process that takes all the CPU, then
> > > >
> > > > gdb httpd PID
> > > > and inside do a 'bt' ( backtrace ), it'll generate a stacktrace
> > > > we can use.
> > > >
> > > >
> > > > Costin
> > > >
> > > > > Thanks,
> > > > > Costas
> > > > > >
> > > > > > Can you try the CVS head, and see if it still happens ?
> > > > > > If so, can you give us more details that would allow to
> > > > > > reproduce it ?
> > > > > >
> > > > > > Messages like 'it doesn't work for me, you figure out why'
> > > > > > are not very helpfull.
> > > > > >
> > > > > > At least enable the debug messages, let it run until it
> > > > > > hungs, then maybe trim the log and send the last entries.
> > > > > > Or use gdb to attach to the problem process and do a
> > > > > > stack trace.
> > > > > >
> > > > > > Costin
> > > > > >
> > > > > > On Wed, 1 May 2002, Costas Stergiou wrote:
> > > > > >
> > > > > > > Hi,
> > > > > > > I have an installation of Apache 1.3.19 + Tomcat 4.0.3
> > > > > > > on a aix4.3 machine with IBM JDK 1.3.0. I have two tomcat
> > > > > > > engines and I use the lb worker of mod_jk to balance user
> > > > > > > request to these two engines.
> > > > > > >
> > > > > > > The problem is that some httpd processes seem to go
> > > > > > > into some cpu performance tasks and start consuming all
> > > > > > > the cpu of the machine (2processors, 2GB mem). After
> > > > > > > some time almost all available CPU is consumed by the
> > > > > > > apache processes. If I kill the child processes that cause
> > > > > > > the problem, the load falls back to normal. At the same
time,
> > > > > > > I notice that I have excessive CPU usage in one of the
> > > > > > > tomcat instances.
> > > > > > >
> > > > > > > The problem keeps recurring all the time (almost every
hour).
> > > > > > > I read in the mail-archives about similar problems but
I
didn't
> > > > > > > find a good answer.
> > > > > > >
> > > > > > > The version of mod_jk is the one in
> > > jakarta-tomcat-connectors-4.0.2.01
> > > > > > > I compiled the source on the same machine (aix).
> > > > > > >
> > > > > > > I have to say that I have noticed similar problems on many
more
> > > > > > > apache installations that have similar installations (apache,
lb
> +
> > > > > > > 2 or more tomcat engines) with older versions of mod_jk
and
> > tomcat.
> > > > > > >
> > > > > > > Actually, the above problem makes the lb worker unusable
since
> > > > > > > I cannot trust the setup in my production environment.
> > > > > > >
> > > > > > > Please, any idea or patches or whatever will be very helpful.
> > > > > > > Thanks very much for any ideas,
> > > > > > > Costas
> > > > > > >
> > > > > > >
> > > > > > >
> > > > > > >
> > > > > >
> > > > > >
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