Resolving Unknown Frames

When the Intel® VTune™ Amplifier finalizes collected data, it uses symbol files (symbol information is included in binary files) to display stack information for each function. If the VTune Amplifier cannot find symbols for system modules used in your application, the stack data displayed in the Bottom-up/Top-down Tree windows and Call Stack pane may be either incomplete or incorrect. The following scenarios are possible:



You run Hotspots or/and Concurrency analysis and your application uses a system API intensively

VTune Amplifier cannot unwind the stack correctly since stacks do not reach user code and stay inside the system modules. Often such stacks may be limited to call sites from system modules. Since VTune Amplifier tries to attach incomplete stacks to previous full stacks via [Unknown frame(s)], you may see [Unknown frame(s)] hotspots when attributing system layers to user code via the Call stack mode option on the Filter bar.

You run the Locks and Waits analysis and your application uses synchronization API causing waits that slow down the application


  1. On Linux, make sure to install the debug info packages available for your system version. For more details, see the Using Debug Information topic.

  2. Re-finalize the result.

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