Intel® Inspector User Guide for Linux* OS

User Guide

  • 2021.4
  • 09/27/2021
  • Public Content
Contents

Investigating Problems Using Interactive Debugging

Sometimes simply knowing the location of a problem is not enough. So the
Intel Inspector
 provides the opportunity to investigate more deeply with an interactive debugging session during analysis.
When you run an interactive debugging session during analysis, the
Intel Inspector
 halts execution at a selected or detected problem. This is more efficient than simply setting a code breakpoint at a reported problem location because the code could execute thousands of times before the conditions that produced the problem occur.
You can choose the supported debugger to use (default is the GNU gdb* debugger). During the debugging session, use the normal commands for the chosen debugger to examine memory, set code breakpoints, and continue execution. Use the command
monitor help
 to view the extended debugger commands provided by the
Intel Inspector
.
Use one of the following ways to initiate an interactive debugging session during analysis so that you see the state of your application code instead of the state of
Intel Inspector
 analysis code:
Objective
Process Summary
Usage
Allow quick investigation of problem(s) of interest.
In a result, choose a problem(s) in the
Summary
 window, right-click to display a context menu, then choose
Debug This Problem
.
Outcome: The
Intel Inspector
:
  • Launches a new analysis, of the same type, optimized to find the selected problem(s).
  • Halts application execution when it detects the selected problem(s) and opens a debugging session.
Typical scenario: After reviewing a problem using result data provided by the
Intel Inspector
, you discover you need more application state information at the time the problem occurred, such as the contents of variables. The
Debug This Problem
 function returns you to the point of the problem, halting execution in a debugging session so you can examine memory and other state information at any point in the call stack.
Delay problem detection until a selected point in the application.
In the
Intel Inspector
, select the
Select analysis start location with debugger
 radio button when configuring an analysis. Start the analysis and wait for the debugging session to open. When execution halts at the entry to
main()
, set a code breakpoint at the point in the application where you want analysis to begin. Continue execution until that point, then enter
monitor begin-analysis
 to turn on analysis and resume execution.
Outcome: Execution halts for each problem detected after you turn on analysis and resume execution. You cannot turn off analysis again.
Typical scenario: You configured the project to limit the application modules for inspection, but you need to narrow analysis focus even further. This option lets you choose an arbitrary location to turn on error detection, allowing faster execution until that point.
Because debugging in conjunction with a threading analysis significantly slows execution:
  • Use this option only if the area targeted for threading analysis has a very short execution time.
  • For best performance, use the
    Debug This Problem
     function to selectively investigate threading issues identified during a non-debug run.
Allow investigation of every detected problem.
In the
Intel Inspector
, select the
Enable debugger when problem detected
 radio button when configuring an analysis.
Outcome: When you run the analysis, the
Intel Inspector
 halts application execution when it detects the first problem and launches a debugging session. Execution halts for each detected problem when you resume execution using normal debugger commands.
Typical scenario: You want to investigate the state of the application for every problem detected.
Because of analysis speed issues, this option is not recommended when detecting data races. It is faster to use the
Debug This Problem
 function to selectively investigate threading problems identified during a non-debug run.

Tips

  • Intel Inspector
     supports interactive debugging only for pure native applications.
  • Intel Inspector
     does not offer interactive debugging for the
    Detect Leaks
     (
    mi1
    ) analysis type because memory and resource leaks are determined after an application terminates and therefore cannot be used to halt execution during analysis. However, you can perform a standard debugger attach to a process launched under this analysis type.
  • Do not recompile your application after generating a result if you plan to use the result
    Debug This Problem
     function.
    Intel Inspector
     cannot guarantee finding the same problem(s) when the binary changes; consequently, it checks for a binary change and reports a warning to prevent rerunning an analysis that may not stop at the selected problem(s).
  • When you use the
    Debug This Problem
     function, the problem list in the new result may differ from the problem list in the source result.
    Intel Inspector
     automatically adjusts the debugging session analysis to return to the selected problem(s) more quickly; however the analysis adjustments do not correspond to individual problem types. Consequently, the
    Intel Inspector
     may detect and report additional problems, but it will break only for a selected problem(s).

Product and Performance Information

1

Performance varies by use, configuration and other factors. Learn more at www.Intel.com/PerformanceIndex.