Some people already know this, but most don't. I am working on a monitor for Tomcat 
using JMeter. The first graph will be the status. I made a mockup in photoshop. The 
actual UI hasn't been coded yet. I'd like to hear people's thoughts and comments.
 
http://cvs.apache.org/~woolfel/server-monitors-status-mockup.jpg 
Here is how I am calculating the load. It is a combination of memory and thread.
 
memory load = (used memory/ max memory) * load factor
the default load factor is 33
 
thread load = (busy threads/ max threads) * load factor
the default load factor is 67
 
tomcat load = memory load + thread load
 
I plan to store the load factor in JMeter's properties file, so users can change the 
value. There are numerous limitation to this approach that I can think of, but I'm 
sure others can think of other limitations.
 
1. a small number of threads could be taking 100% of the CPU, like XML. which would 
mean both memory and thread don't tell you accurate what the load is
 
2. a large number of concurrent requests for static files may not place load on the 
system
 
3. memory usage could be high, but the system may be responding within acceptable 
ranges
 
The load calculation at this point is at a high level, but I feel it is still useful. 
Ultimately the load calculation will have to be specific to the actual webapps. Since 
JMeter and the new monitor will be extensible, users should be able to provide their 
own class to calculate load. Once I get a working version done. I can't say when it 
will get done, but I am actively working on it.
 
peter lin
 


---------------------------------
Do you Yahoo!?
Protect your identity with Yahoo! Mail AddressGuard

Reply via email to