- System requirements
- Profiler architecture
- Running the profiler
- Profiler activation
- Start profiling
- Solving performance problems
- CPU profiling
- CPU usage estimation
- Sampling
- Asynchronous sampling
- Tracing
- Call counting
- CPU tab
- What-if: an ability to ignore particular methods or focus on particular methods only
- Comparing performance snapshots
- Sampling settings
- Tracing settings
- Threads
- Deadlock detector
- Memory profiling
- Garbage collection
- Monitor profiling
- Exception profiling
- Probes: monitor events of various kinds
- Performance Charts
- Inspections: automatic recognition of typical problems
- Automatically trigger actions on event
- Summary, snapshot annotation, automatic deobfuscation
- Time measurement (CPU time, wall time)
- Filters
- Snapshot directory customization
- Export of profiling results to HTML, CSV, XML, plain text
- Profiler Java API
- Profiler HTTP API
- Command line tool to control profiling
- Settings
- FAQ: How to profile in my scenario?
Tracing
Tracing is one of the CPU profiling modes.
When tracing is used, the profiler instruments the bytecode of the profiled application for recording time spent inside each profiled method. Both times and invocation counts are available.
Use profiler toolbar to start CPU tracing as shown on the picture below. There are also alternate methods to start CPU profiling.
Overhead
Although tracing provides more information, it has its drawbacks. First, it may noticeably slow down the profiled application, because the profiler executes special code on each enter to and exit from the methods being profiled. The greater the number of method invocations in the profiled application, the lower its speed when tracing is turned on.
The second drawback is that, since this mode affects the execution speed of the profiled application, the times recorded in this mode may be less adequate than times recorded with sampling. Please use this mode only if you really need method invocation counts.
Also, the probes for the high-level statistics, if enabled, may impose additional overhead.
See also: Profiling overhead: how to reduce or avoid.
Tracing settings
To control profiling overhead and accuracy of the results use CPU tracing settings.
CPU tracing will be disabled if the startup option
disabletracing or
disableall is specified.