Following is a brief description of the
structure of 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
calledBBOO_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 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 defintion 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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