ANALYZEALLOCATION

Section: User Commands (1)
Updated: March 28, 1996
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NAME

AnalyzeAllocation - analyze memory allocation statistics.

SYNOPSIS

AnalyzeAllocation [-help] [-v] file

DESCRIPTION

AnalyzeAllocation analyzes the allocation statistics gathered by the Foundation Framework (see NSDebug.h). To gather all allocation statistics, you can set NSKeepAllocationStatistics to YES in your environment and then run the application. This records allocation statistics in a file named /tmp/alloc_stats_application_pid. This file gets very large very quickly, in addition to making your program run much more slowly, so it's important not to run too much of your program with the NSKeepAllocationStatistics environment variable turned on. Instead, run a specific task, then turn the environment variable off.

As an alternative, you can control what portions of the running application are measured by setting the global variable NSKeepAllocationStatistics to YES when you want to gather statistics and NO when you do not. This variable is defined in the Foundation Framework file NSDebug.h.

After you have gathered statistics, you run the AnalyzeAllocation command to analyze them. AnalyzeAllocation with no options prints a table that summarizes the allocation statistics. For each class, the table provides the following information:

retain: Invocations of the default retain implementation
release: Invocations of the default release implementation
iretain: Invocations of an override of retain
irelease: Invocations of an override of release
autorelease: Invocations of autorelease
copy: Invocations of copy
instances: Number of instances still alive
max: Maximum number of instances at one time
total: Total number of instances created
class: Name of the class

The -v option prints a detailed analysis for each class, consisting of:

    The number of objects allocated

    The number of objects deallocated

    Shortest lifetime (in seconds) of any object of this class

    Median lifetime (in seconds) of any object of this class

    Maximum lifetime (in seconds) of any object of this class

    Number of ephemeral objects, objects that lasted less than 0.01 seconds

    Minimum number of retains on any object of this class

    Median number of retains on all objects of this class

    Maximum number of retains on any object of this class

    Minimum number of releases on any object of this class

    Median number of releases on all objects of this class

    Maximum number of releases on any object of this class

    Minimum number of invocations of an override of retain for any object of this class

    Median number of invocations of an override of retain on all objects

    Maximum number of invocations of an override of retain on any object

    Minimum number of invocations of an override of release on any object

    Median number of invocations of an override of release on all objects

    Maximum number of invocations of an override of release on any object

    Minimum number of autoreleases on any object

    Median number of autoreleases on all objects

    Maximum number of autoreleases on any object

    Minimum number of copies on any object

    Median number of copies on all objects

    Maximum number of copies on any object

    Minimum number of retains on any instance of this class

    Median number of retains on all objects

    Maximum number of retains on any object

OPTIONS

-help: Displays a message describing how to use AnalyzeAllocation.
-v: Displays a different set of statistics as described above.
file: The file to be analyzed. Its name has the form /tmp/alloc_stats_appName_pid

EXAMPLES

# setenv NSKeepAllocationStatistics YES
# /NextDeveloper/Demos/TextEdit.app/TextEdit
run for a while, then quit
# unsetenv NSKeepAllocationStatistics
# AnalyzeAllocation -v /tmp/alloc_stats_Edit_*

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