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.