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VM Tracker Instrument

Overview

Instrument Description

The VM Tracker instrument captures information about virtual memory usage by a process. It can record information from a single process only.

Supported Platforms

iOS

OS X

Related Profiling Templates

Allocations Profiling Template

System Trace Profiling Template

Timeline Pane

The timeline pane displays virtual memory information based on the instrument’s Style configuration.

Record Settings

This instrument doesn’t have any record settings you can configure.

Display Settings

Click the Display Settings button (image: ../Art/instruments_displaysettings_button_inline_2x.png) in the inspector pane to customize the following display settings.

Track Display Settings

These settings control how information is displayed in the timeline pane.

Setting

Description

Options

Style

How information is presented.

  • Dirty, Resident Sizes: The size of the regions identified.

  • # Regions: The number of regions identified.

Snapshots

The following snapshot display settings are available.

Setting

Description

Automatic Snapshotting

When profiling with VM Tracker, the target process is analyzed in intervals. Each analysis is considered a snapshot. This setting allows you to specify how often the instrument looks at your app and records a snapshot. You can specify an interval in seconds, or click Snapshot Now to record a snapshot at any time while profiling. Also displays a status, indicating when snapshotting is in progress or when the next snapshot will occur.

VM Options

The following VM options display settings are available.

Setting

State

Coalesce Regions

On by default.

Show Full Paths

Off by default.

Protection Filters

These filters are only enabled when you are viewing the Region Map detail type.

Setting

State

Readable

Off by default.

Writable

Off by default.

Executable

Off by default.

Detail Pane Columns

Summary Detail Type

The following summary columns are available in the detail pane.

Column name

Definition

% All Dirty

The percentage of memory currently being used that must be written to secondary storage before being reused.

% of Res.

The percentage of memory used based on the type displayed.

Type

The name of the memory being used.

# Regs

The total number of virtual memory registers used.

Path

The path to the file on which the executable performed the operation.

Resident Size

The amount of actual memory being used.

Dirty Size

The amount of memory currently being used that must be written to secondary storage before being reused.

Virtual Size

The size of the virtual memory.

Res. %

The percentage of resident memory compared to the amount of virtual memory available.

Protections

The permissions allowed by the operation.

Regions Map Detail Type

The following region map columns are available in the detail pane.

Column name

Definition

Type

The name of the memory being used.

Address Range

The address range of the virtual memory.

Dirty Size

The amount of memory currently being used that must be written to secondary storage before being reused.

Resident Size

The amount of actual memory being used.

Virtual Size

The size of the virtual memory.

Resident %

The percentage of actual memory being used for the operation.

Protections

The permissions allowed by the operation.

Path

Name corresponding to the process performing the operation.