The following is a brief description of the structure of
IBM® WebSphere® Application Server:
WebSphere Application Server for z/OS is made of multiple address
spaces. The components are a single Control Region running authorized
code, and multiple Server Regions running unauthorized or application
code. Workload manager (WLM) determines how many server regions to start
or stop based on a policy defined for it by the systems programmer. IBM
recommends that the policy is that 85% of the workload finishes in .5
second.
The control region runs with 25 threads. You should not have to change
this in production. If, however, debugging is necessary and you are
running WebSphere Application Server on 4.0.1, a check box in the Systems
Management End User Interface (SMEUI) called Production J2EE Server
makes this 1 thread. If Production J2EE Server is checked, there are 25
threads, if it is not checked, 1 thread. If it is not checked, the option
directly below the production J2EE server called Debugger Allowed
is available for selection.
For WebSphere Application Server Version 4.0.1
The Server region has two different ways to adjust the number of
threads available. Both exist within the Server definition in the SMEUI.
The original and first option in the server definition is a check box
called Isolation Policy.
If you select one transaction per server region, server regions
are single-threaded. If you select multiple transactions per server
region, a multi-threaded server region starts with three threads. The
latest addition to this is an environment variable called
BBOO_WORKLOAD_PROFILE=value. If specified, this environment
variable overrides the value for the Isolation Policy check box.
Environment variables are explained in Appendix A in WebSphere
Application Server V4.0.1 for z/OS and OS/390 Installation and
Customization GA22-7834-05.
BBOO_WORKLOAD_PROFILE=value
Controls workload-pertinent decisions made by the WebSphere Application
Server for z/OS runtime, such as the number of threads used in the server
region. The default value is NORMAL, which is the appropriate value for
most applications. Consider using one of the other values when your
application requires more threads.
NORMAL
Gives you the thread count dictated by WebSphere Application Server for
z/OS, which is either one (single-threaded) or three (multi-threaded).
IOBOUND This value is the default.
Use IOBOUND if you want more threads in applications that perform
I/O-intensive processing on z/OS. The number of threads is calculated
based on your number of CPUs:
MIN(30, MAX(5,(Number of CPUs*3))).
CPUBOUND
Use CPUBOUND if you want more threads in applications that perform
processor-intensive operations on z/OS. The number of threads is
calculated based on your number of CPUs, and cannot be less than three
MAX((Number of CPUs-1),3).
LONGWAIT
Use LONGWAIT for application processing that involves sending or
receiving information across a network (forty threads per server region).
Example: BBOO_WORKLOAD_PROFILE=NORMAL
For WebSphere Application Server Version 5.0
You can change the variable server_region_workload_profile in
the Administrative Console by clicking on Environment and then Manage
WebSphere variables. From here it is the same behavior as any other
environment variable.
For scope, decide whether to place the variable at the node or server
level. If the variable exists, you can modify it; otherwise, add
server_region_workload_profile as new.
Search the WebSphere Application Server for z/OS Information
Center for Topology Planning and Performance for the definition of
server_region_workload_profile.
server_region_workload_profile=value
Controls workload-pertinent decisions made by the WebSphere Application
Server for z/OS runtime, such as the number of threads used in the server
region. The default value is NORMAL, which is the appropriate value for
most applications. Consider using one of the other values when your
application requires more threads.
ISOLATE
Gives you the thread count of one (single-threaded).
IOBOUND This value is the default.
Use IOBOUND if you want more threads in applications that perform
I/O-intensive processing on z/OS. The number of threads is calculated
based on your number of CPUs
MIN(30, MAX(5,(Number of CPUs*3))).
CPUBOUND
Use CPUBOUND if you want more threads in applications that perform
processor-intensive operations on z/OS. The number of threads is
calculated based on your number of CPUs, and cannot be less than three
MAX((Number of CPUs-1),3).
LONGWAIT
Use LONGWAIT for application processing that involves sending or
receiving information across a network (forty threads per server region).
Example: BBOO_WORKLOAD_PROFILE=NORMAL
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