The approach inspectIT Ocelot takes for instrumenting is fundamentally different from the approach of most other JVM instrumentation agents. InspectIT Ocelot does not instrument classes when they are loaded, the instrumentation is performed purely asynchronous in the background.
In this background task inspectIT Ocelot essentially looks at every loaded class and performs an instrumentation if required by the active configuration. Hereby, the agent manages the classes he has to analyze in a queue. This queue is processed in batches to ensure that no CPU resources are blocked if they are required by the instrumented application. The batching is configurable using the
inspectit: instrumentation: # settings for fine-tuning the instrumentation process internal: # the time to pause between executing batches of class instrumentation updates inter-batch-delay: 50ms # defines how many classes are checked at once for updates of their configuration per batch class-configuration-check-batch-size: 1000 # defines the maximum number of classes which are instrumented per batch class-retransform-batch-size: 10 # defines how often the agent should check if new classes have been defined. new-class-discovery-interval: 10s # defines how often the new class discovery is performed after a new class has been loaded num-class-discovery-trials: 2 # defines whether orphan action classes are recycled or new classes should be injected instead recyclingOldActionClasses: true
In addition, the size of the instrumentation queue can be used as an indicator for the instrumentation progress. It is accessible via the self-monitoring of the agent.
InspectIT allows you to perform instrumentation by injecting custom code into your application.
If your JVM has a
SecurityManager enabled, you might also want to control the
ProtectionDomain of these injected classes.
By default, inspectIT will use its own
ProtectionDomain for injected classes.
Alternatively, you can make inspectIT to use the
ProtectionDomain for which the action is being created using the following configuration:
inspectit: instrumentation: internal: use-inspectit-protection-domain: false
Synchronous instrumentation (BETA!)
Enabling synchronous instrumentation in Java 8 environments will result in significant boot time performance degradation!
See See: JDK-7018422
By default, all instrumentation is performed purely asynchronously in the background. There may be situations where this is not appropriate and a class must be instrumented directly at the first load, e.g. in batch processes.
InspectIT can be configured to instrumented classes on first class load by updating the following configuration:
inspectit: instrumentation: internal: async: false