ODRs are intelligent routers for SIP and HTTP traffic, acting as intermediaries for
application servers and webs ervers. There are many factors that affect ODR performance; in order to
get the optimal performance from your ODRs, it is sometimes necessary to tune them.
Before you begin
- Tune Java™ virtual machines. For more information, read
about tuning the IBM® virtual machine for Java.
- Remove all tracing information except for *=info, because this type of tracing
impacts ODR performance. To change the tracing information, perform the following steps:
- Select .
- Ensure that only *=info is specified.
- The ODR should never be constrained by either CPU or memory usage. Therefore, when you install
the ODR in an environment with server virtualization, configure the virtual machine or LPAR in which
the ODR runs in dedicated processor mode, or configure it in a mode that guarantees the ODR receives
a sufficient amount of CPU resources and dedicated memory when the ODR runs.
- Binary Trace Facility (BTF) has minimal impact on performance and can be left enabled
About this task
The default settings of the ODR work for most people, most of the time. For your
installation, it may be necessary to carry out some or all of the following steps to obtain maximum
performance. The steps are prioritized in order of importance.
Procedure
- Check the JVM settings. For more information about the JVM settings, read about modifying the
JVM heap size for the on demand router.
HP and Sun provide additional tuning parameters to optimize garbage collection. For
generational garbage collection JVMs such as Sun and HP, or IBM's J9 JVM when using gencon garbage
collection, set the permanent memory region to approximately 100MB to encompass the base 90MB foot
print that exists in the ODR. Further, a SurvivorRation of 16 further optimizes processing in the
young generation. On HP JVM, you can turn NIO to yield an increase in performance by using the
-Djava.nio.channels.spi.SelectorProvider=sun.nio.ch.DevPollSelectorProvider selector
provider and disabling the extra poll before a read: -XX:-ExtraPollBeforeRead.
- Tune the connection keep alive settings. For more information, read about tuning ODR persistent
connections.
- Tune the ODR maximum connections per server. For more information, read about tuning ODR
maximum connections.
- Disable ODR caching when not in use. When the ODR caching is enabled, the ODR must go through the process of determining whether a
request should be cached, then examine the cache repository to check whether the request was
previously cached. This additional overhead on the ODR may create a bottleneck at the ODR.
- Disable access logging if not needed. If you do need access logging, then the proxy logging is preferred over the HTTP Channel/NCSA
logging as the proxy access logging happens outside of the request/reply path. Thus, it does not
affect the response time of the request. Access logging on a fairly fast disk is typically 5%
overhead, but the percentage is highly dependant on disk performance.
- Use the same thread group for both inbound and outbound work, which will avoid moving requests
across threads and eliminates the resulting overhead. The ODR has a set of threads that tune itself under most circumstances. Queuing and throttling
requests are dispatched to the default thread pool, which you can tune so that it will only handle
the overflow requests. The primary thread group will continue to handle most requests. All requests
on the thread pool are asynchronous with no blocking calls, so the number should not be more than
one or two threads per CPU. Complete the following steps to use the same thread group for both
inbound and outbound work:
- Select .
- Specify combineSelectors for the name.
- Specify 1 for the value.
- Click OK.
- Click Save.