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From William Kaufman <WKauf...@viquity.com>
Subject RE: tomcat thread hogs CPU - is this a bug ?
Date Wed, 09 May 2001 14:28:02 GMT
I'm running it 3.2 on NT, not HP-UX, but Tomcat does start up several
threads, and few of them are doing anything at any time.

Try dumping the stacks by pressing the Java "break" key.  (I think that's
Control+Y on Unix.  And, of course, there's the matching signal which you
can send with the "kill" command, if you're running Tomcat in the
background.)  If it's like NT (which I'd expect it is), you'll find that
most of them are either blocked on sockets waiting for new requests; or
blocked on Object.wait(), waiting to do some work.

And, of course, this is no bad thing, assuming "wait" is properly
implemented in your JVM--doesn't take up any CPU, can be swapped out as
needed,...

                                                            -- Bill K.


> -----Original Message-----
> From: Martin, Brian [mailto:BMartin@AlamoLocal.com]
> Sent: Wednesday, May 09, 2001 6:46 AM
> To: 'tomcat-user@jakarta.apache.org'
> Subject: tomcat thread hogs CPU - is this a bug ?
> 
> 
> 
> I am running tomcat 3.2 on an dual cpu HPUX-11.0 box, 
> using IIS on the front end on an NT box.
> 
> when I look at the thread list (using glance) for the tomcat process,
> i can see 42 threads, but only one of them is showing high cpu usage
> in this screen shot, it is thread id 8168.
> 
> why are there so many threads at 0 % ?  
> 
> is anyony else running tomcat on hpux ? if yes, can you email me your
> screen captures showing performance related stuff. I am 
> trying to figure
> out whether or not some of the things that i am looking at 
> are 'normal'
> or just my system.
> 
> is there a way to tell what each thread is doing ?
> 
> 
> 
> 
> Thread List PID:  2805, java            PPID:  2803 euid:   101 User:
> weblogic
>            CPU Util    CPU Tm      Phys          Logl
> Block
>  TID    (  200% max)    Cum       IO Rate      IO Rate   
> Scheduler  Pri   On
> --------------------------------------------------------------
> --------------
>   8150    0.0/   0.0     1.8    0.0/   0.0    0.0/   0.0      
> HPUX  154
> SYSTM
>   8167    0.0/   0.0     0.0    0.0/   0.0    0.0/   0.0      
> HPUX  154
> SYSTM
>   8168   46.8/   6.5  3950.7    0.0/   0.0    0.0/   0.0      
> HPUX  239
> PRI  
>   8169    0.0/   0.0     1.0    0.0/   0.0    0.0/   0.0      
> HPUX  154
> SYSTM
>   8170    0.0/   0.0     1.5    0.0/   0.0    0.0/   0.0      
> HPUX  154
> SYSTM
>   8171    0.2/   0.1    79.6    0.0/   0.0    0.0/   0.0      
> HPUX  168
> SLEEP
>   8172    0.0/   0.0     0.0    0.0/   0.0    0.0/   0.0      
> HPUX  154
> SYSTM
>   8173    0.7/   0.1    33.5    0.0/   0.0    8.1/   0.8      
> HPUX  154
> SYSTM
>   8174    0.0/   0.0     3.6    0.0/   0.0    0.0/   0.0      
> HPUX  168
> SLEEP
>   8175    0.0/   0.0    11.2    0.0/   0.0    0.0/  10.9      
> HPUX  154
> SYSTM
>   8176    0.0/   0.0     4.3    0.0/   0.0    0.0/   4.1      
> HPUX  154
> SYSTM
>   8177    4.8/   0.1    57.8    0.0/   0.0 3564.2/  56.9      
> HPUX  192
> PRI
>   8178    0.0/   0.2   108.1    0.0/   0.0    0.0/ 103.3      
> HPUX  154
> SYSTM
>   8179    0.0/   0.0    16.0    0.0/   0.0    0.0/  15.6      
> HPUX  154
> SYSTM
>   8180    7.6/   0.3   186.5    0.0/   0.0 5402.8/ 188.7      
> HPUX  192
> PRI
>   8181    4.0/   0.1    47.5    0.0/   0.0 2815.3/  49.6      
> HPUX  154
> STRMS
>   8182    0.0/   0.3   155.4    0.0/   0.0    0.0/ 159.6      
> HPUX  154
> SYSTM
>   8183    4.7/   0.3   164.6    0.0/   0.0 2677.0/ 169.5      
> HPUX  154
> SYSTM
>   8184    4.7/   0.3   207.6    0.0/   0.0 2556.4/ 209.6      
> HPUX  193
> PRI
>   8185    0.0/   0.0     0.2    0.0/   0.0    0.0/   0.0      
> HPUX  154
> SYSTM
>   8190    0.0/   0.0     0.3    0.0/   0.0    0.0/   0.0      
> HPUX  154
> SYSTM
>   8191    0.0/   0.0     3.9    0.0/   0.0    0.0/   0.0      
> HPUX  154
> SYSTM
>   8192    0.0/   0.0     0.0    0.0/   0.0    0.0/   0.0      
> HPUX  154
> SYSTM
>   8193    0.0/   0.0     4.1    0.0/   0.0    0.0/   0.0      
> HPUX  154
> SYSTM
>   8194    0.0/   0.0     0.2    0.0/   0.0    0.0/   0.0      
> HPUX  154
> SYSTM
>   8195    0.2/   0.1    50.7    0.0/   0.0    0.0/   0.0      
> HPUX  154
> SLEEP
>   8196    0.0/   0.0     0.3    0.0/   0.0    0.0/   0.0      
> HPUX  154
> SYSTM
>   8197    0.0/   0.0     4.6    0.0/   0.0    0.0/   0.0      
> HPUX  154
> SYSTM
>  29571    0.0/   0.1     7.2    0.0/   0.0    0.0/   0.0      
> HPUX  154
> SYSTM
>   8546    0.0/   0.0     0.0    0.0/   0.0    0.0/   0.0      
> HPUX  154
> SYSTM
>   8547    0.0/   0.0     0.0    0.0/   0.0    0.0/   0.0      
> HPUX  154
> SYSTM
>   8548    0.0/   0.0     0.0    0.0/   0.0    0.0/   0.0      
> HPUX  154
> SYSTM
>   8549    0.0/   0.0     0.0    0.0/   0.0    0.0/   0.0      
> HPUX  154
> SYSTM
>   8550    0.0/   0.0     0.0    0.0/   0.0    0.0/   0.0      
> HPUX  154
> SYSTM
>   8551    0.0/   0.0     0.0    0.0/   0.0    0.0/   0.0      
> HPUX  154
> SYSTM
>   8552    0.0/   0.0     0.0    0.0/   0.0    0.0/   0.0      
> HPUX  154
> SYSTM
>   8553    0.0/   0.0     0.0    0.0/   0.0    0.0/   0.0      
> HPUX  154
> SYSTM
> 
> 
> Brian Martin
> Unix Administrator
> Alamo, Local Market Division
> (440) 715-3549
> 

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