Dialog Box: Custom Analysis

Intel® Inspector User Guide for Windows* OS

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ID 767798

Date 5/15/2022

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Dialog Box: Custom Analysis

(One way) To access this Intel Inspector dialog box:

Click the Copy button on the Analysis Type-Memory Errors or Analysis Type-Threading Errors pane.
Click the Copy button or Edit button on the Analysis Type-Custom pane.

Use this dialog box to create or edit custom analyses.

Use This	To Do This
Analysis name field	View or change the default name that distinguishes this custom analysis type from other analysis types when you use the graphical user interface.
Description field	View or change the default detailed information that distinguishes this custom analysis type from other analysis types.
Command-line name field	View or change the default identifier that distinguishes this custom analysis type from other analysis types when you use the command-line interface.
Analysis identifier field	View or change the {at} identifier that distinguishes results produced by this custom analysis type from other results. For example: ti2c, where: ti2 represents the preset analysis type on which the custom analysis type is based c represents custom

Configuration Settings for Custom Analysis Types Based on Memory Error Analysis Types

Use the Properties region of the dialog box to configure the custom analysis type.

The following table describes the purpose, usefulness, and cost (low, medium, high, or proportional in terms of time and resources) for each configuration setting in a custom analysis type based on a memory error analysis type. (The settings are listed in alphabetical order.)

Setting	Purpose, Usefulness, and Cost
Analyze stack accesses	Available only if Detect invalid memory accesses is selected. Select to analyze invalid and uninitialized accesses to thread stacks. Selecting is useful when: You want as thorough an analysis as possible. An application calls `alloca()`. High cost. Recommendation: Select the first time you analyze an application and periodically thereafter. Select to analyze automatic variables.
Defer memory deallocation (previously called Byte limit before reallocation)	Available only if Detect invalid memory accesses and Enable enhanced dangling pointer check are selected. Select to have the Intel Inspector prevent freed memory blocks from immediately returning to the pool of available memory. Selecting is useful for discovering if an application tries to use memory after freeing it. High cost if an application is performing many allocations/deallocations. Recommendation: Select to improve analysis quality if the cost is not too high.
Detect invalid memory accesses (split from Detect invalid/uninitialized accesses)	Select to detect problems where a read or write instruction references memory that is logically or physically invalid. Selecting is useful to ensure an application accesses only valid memory. Medium cost. Recommendation: Select. NOTE: May change application behavior by initializing memory that may normally be uninitialized. If your application reads this normally uninitialized memory, it may: Simply miscalculate a value. Treat the memory as a pointer, deference it, and crash during analysis.
Detect leaks at application exit (previously called Detect memory leaks upon application exit)	Select to report typical memory leaks in which the application allocates a memory block, never releases it, and doesn’t keep a pointer to the block (e.g. unreachable memory blocks). Selecting is useful when an application: Runs out of memory. Appears to be using more memory than expected. Extremely low cost – especially if used only with Remove duplicates selected. Recommendation: Select.
Detect resource leaks	Select to detect open kernel and GDI handles when the application ends. For example, the application may open a file, get its handle, but never close or release that handle until it stops running. On Windows, GDI resources are limited, and the application may experience some drawing issues if it uses more than ~10,000 of these types of handles at once (pen, bitmap, brush, etc.) Selecting is useful if you see constant growth in acquired kernel and GDI objects in the system task manager for your process. Low cost. Recommendation: Select unless you want to focus on memory problems exclusively.
Detect still-allocated memory at application exit (previously called Report still-allocated memory at application exit)	Available only if Detect leaks at application exit is selected. Select to report typical memory leaks in which the application allocates a memory block, doesn’t deallocate it, but a valid variable still holds a pointer to that block when the application ends (e.g. reachable memory blocks). Cost is proportional to the number of memory blocks still allocated when the application stops executing. Recommendation: Select to investigate memory growth.
Detect uninitialized memory reads (split from Detect invalid/uninitialized accesses)	Available only if Detect invalid memory accesses is selected. Select to detect problems where a read instruction accesses an uninitialized memory location. Selecting is useful when an application: Exhibits unexpected behavior. Shows evidence of uninitialized values in computations. High cost. Recommendation: Deselect. NOTE: May change application behavior by initializing memory that may normally be uninitialized. If your application reads this normally uninitialized memory, it may: Simply miscalculate a value. Treat the memory as a pointer, deference it, and crash during analysis.
Enable enhanced dangling pointer check	Available only if Detect invalid memory accesses is selected. Select to detect if an application is trying to access memory after it was logically freed. May be higher cost if an application is performing many allocations/deallocations, and the Defer memory deallocation list value is smaller than the amount of memory the application allocates. Recommendation: Select when an application exhibits unexpected behavior you suspect may be caused by a dangling pointer. NOTE: Changes application behavior by intercepting calls to deallocators and deferring actual deallocation. Enhanced dangling pointer check is not supported for new/delete and new[]/delete[] allocation/deallocation pairs.
Enable guard zones	Available only if Detect invalid memory accesses is selected. Use in conjunction with Guard zone size to show offset information if the Intel Inspector detects memory use beyond the end of an allocated block. Selecting is useful when: An application exhibits unexpected behavior. You need more context about heap allocations to interpret Invalid memory access problems. Cost is proportional to number of allocations. Recommendation: Select unless: Intel Inspector runs out of memory. An application becomes destabilized. NOTE: May change application behavior. Increases the amount of memory the Intel Inspector uses. Intel Inspector creates guard zones only at the end of allocated space, not at the start of allocated space.
Enable memory growth detection (previously called Enable interactive memory growth detection)	Select to enable buttons in the GUI that let you send commands during application execution. This will show you a list of reachable and unreachable memory blocks for a time segment. Selecting is useful for modeling memory usage patterns and ensuring a transactional application deallocates all memory allocations after a transaction completes. Use in conjunction with the Reset Growth Tracking and Measure Growth buttons during analysis. Low cost.
Enable on-demand leak detection (previously called Enable on-demand memory leak detection)	Select to enable buttons in the GUI that let you send “leak” commands. This will show you a list of unreachable memory blocks for a time segment. Selecting is useful for checking for memory leaks in an application that never exits, or in only the portion of an application for which you are responsible. Use in conjunction with the Reset Leak Tracking and Find Leaks buttons during analysis. Cost is proportional to the number of allocations.
Guard zone size (previously called Guard zone byte size)	Available only if Detect invalid memory accesses and Enable guard zones are selected. Use in conjunction with Enable guard zones to set the number of bytes beyond the allocated block of memory the Intel Inspector reserves to identify Invalid memory access problems related to the allocation. Setting is useful when: An application exhibits unexpected behavior. You need more context about heap allocations to interpret Invalid memory access problems. Cost is proportional to number of allocations. Recommendation: Set unless: Intel Inspector runs out of memory. An application becomes destabilized. NOTE: May change application behavior. Increases the amount of memory the Intel Inspector uses. Intel Inspector creates guard zones only at the end of allocated space, not at the start of allocated space.
Maximum number of leaks shown in result (previously called Maximum memory leaks)	Use to set the maximum number of leaks the Intel Inspector shows in a result after analysis is complete. A zero setting shows all detected memory leaks. Cost is proportional to the number of leaks. Recommendation: Use the default value unless you want an exhaustive list of all leaks. TIP: Even the default value can generate an unmanageable number of leaks. Consider sorting the displayed memory leaks by Object Size, fixing the largest leaks, and then re-inspecting your application. Or use the on-demand leak detection feature to narrow your focus and eat the elephant one bite at a time.
Remove duplicates	Deselect to show all occurrences of a detected problem in the Code Locations pane. Deselecting is: Useful when you need to fully visualize all threads and problem occurrences in relation to time Low cost in terms of time; however, the number of duplicate errors could crowd out the number of unique errors. Recommendation: Select.
Revert to previous uninitialized memory algorithm (not recommended)	Available only if Detect uninitialized memory reads is selected. The current algorithm for detecting uninitialized memory reads decreases false positives but increases analysis time and memory overhead. Select to use the previous version of the algorithm. Recommendation: Deselect.
Stack frame depth	Use to provide more or less call stack context for detected errors. A high setting is useful when analyzing highly object-oriented applications. A higher number does not significantly impact cost. Recommendation: Use only as large a value as an application requires to display complete call paths.

Configuration Settings for Custom Analysis Types Based on Threading Error Analysis Types

Use the Properties region of the dialog box to configure the custom analysis type.

The following table describes the purpose, usefulness, and cost (low, medium, high, or proportional in terms of time and resources) for each configuration setting in a custom analysis type based on a threading error analysis type. (The settings are listed in alphabetical order.)

Setting	Purpose, Usefulness, and Cost
Cross-thread stack access detection	Use to set the alert mechanism for when a thread accesses stack memory of another thread. The alert mechanism helps you decide if this is an issue that requires handling. All options are low cost if Detect data races is selected. Recommendation: Use Hide problems/Hide warnings if using an OpenMP* or oneAPI Threading Building Blocks (oneTBB) programming model; or if cross-thread stack accesses are anticipated. Also select Detect races on stack. Use Hide problems/Show warnings if cross-thread stack accesses are not anticipated. Also deselect Detect data races on stack. Use Show problems/Hide warnings if cross-thread stack accesses are not anticipated but a previous analysis indicated they exist and you are not using an OpenMP* or oneAPI Threading Building Blocks (oneTBB) programming model. Also deselect Detect data races on stack.
Detect data races	Select to detect problems where multiple threads access the same memory location without proper synchronization and at least one access is a write. Selecting is useful when you suspect data races that are not yet evident. High cost. Recommendation: Select. Consider also deselecting Use maximum resources to reduce cost.
Detect data races on stack (previously called Detect data races on stack accesses)	Available only if Detect data races is selected. Select to detect data races for variables allocated on the stack. Selecting is useful when threads in an application share variables from the stack and you suspect data races on the variables. High cost. Recommendation: Deselect. If you select, consider also deselecting Use maximum resources to reduce cost.
Detect deadlocks	Select to detect problems where two or more threads are waiting for the other to release resources, but none of the threads releases the resources. Thus no thread can proceed. Selecting is useful when you want to troubleshoot the location of a deadlock. Low cost.
Detect lock hierarchy violations	Select to detect problems where the acquisition hierarchy order of multiple synchronization objects in one thread differs from the acquisition hierarchy order in another thread, and could cause a deadlock under certain conditions. Selecting is useful when an application has complicated synchronization and it is hard to verify correctness. Low cost unless an application has a significant number of locks.
Filter guaranteed atomics	Available only if Detect data races is selected. Select to ignore data races on guaranteed atomic operations on the Intel® P6 processor family or newer. For details, please refer to the Guaranteed Atomic Operations section of the Intel® 64 and IA-32 Architectures Software Developer’s Manual, Volume 3A. Selecting is useful if you observe many false data race reports on simple operations like Load or Store to shared variables and the size of those variables is less than the processor cache line size. Do not select this option if you develop cross-platform code that should work on other architectures. Selecting this option might also hide true-races on variables that were properly aligned during this run but might not be aligned in general, e.g., if it just works “by chance”. Low cost. Recommendations: Use this option with caution only if you observe many false reports on simple memory operations.
Race analysis byte granularity (previously called Memory access byte granularity)	Available only if Detect data races is selected. Use to set the size of the smallest memory block the Intel Inspector considers a single block of memory when determining if non-synchronized accesses to a memory block constitute a data race. Selecting is useful to control memory consumption during analysis for some applications. High cost when set to 1 byte. Recommendation: Set to 4 unless you continually see data races based on safe access to smaller memory blocks. If so, reset to 1.
Remove duplicates	Deselect to show all occurrences of a detected problem in the Code Locations pane. Deselecting is: Useful when you need to fully visualize all threads and problem occurrences in relation to time Low cost in terms of time; however, the number of duplicate errors could crowd out the number of unique errors. Recommendation: Select.
Save stack on first access	Available only if Detect data races is selected. Select to show as much information as possible on all threads involved in a data race. Selecting is useful when investigating complex data race problems. High cost. Recommendation: Deselect on initial analysis runs. Select only when you need the maximum information and context about all threads involved in a data race to solve the problem.
Save stack on lock creation	Select to show creation information on synchronization objects involved in deadlocks, lock hierarchy violations, and data races. Selecting is useful when acquisition stacks are not sufficient to understand the problem. Low cost.
Save stack on memory allocation (previously called Save stack on allocation)	Available only if Detect data races is selected. Select to identify the allocation site of dynamically allocated memory objects involved in data races. Medium cost. Recommendation: Select when you need to identify the object hierarchy of low-level objects involved in data races. For example: If object R is involved in a data race and is instantiated within objects O1, O2, and O3, the allocation call stack can help you identify which encapsulating object is not properly protecting access to object R.
Stack frame depth	Use to provide more or less call stack context for detected errors. A high setting is useful when analyzing highly object-oriented applications. A higher number does not significantly impact cost with one exception: Choosing a higher number plus selecting Save stack on first access increases cost. Recommendation: Use only as large a value as an application requires to display complete call paths.
Terminate on deadlock	Available only if Detect deadlocks is selected. Select to stop analysis and application execution if the Intel Inspector detects a deadlock. Selecting is useful when running your application as part of a kernel or unit testing suite. Low cost. Recommendation: Deselect. Instead, use the corresponding knob in the command line interface to perform kernel or unit testing in a nightly scenario. If the Intel Inspector identifies a deadlock, decide if it is appropriate to continue analysis.
Use maximum resources	Select to potentially find more problems. High cost. Recommendation: Deselect to run a quicker analysis that should find most of your data race and cross-thread stack access problems. Once you have found and fixed these problems, select to get more complete analysis coverage of possible data race and cross-thread stack access problems.

Parent topic: User Interface Reference

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Intel® Inspector User Guide for Windows* OS

Dialog Box: Custom Analysis

Configuration Settings for Custom Analysis Types Based on Memory Error Analysis Types

Configuration Settings for Custom Analysis Types Based on Threading Error Analysis Types

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