I/O Activity Instrument
Overview
Instrument Description |
The I/O Activity instrument captures information about I/O events. |
Supported Platforms |
iOS |
Related Profiling Templates |
Timeline Pane
The timeline pane displays the following information, based on the instrument’s configuration:
Display name |
Definition |
---|---|
Sample Number (#) |
The sequence number of the event. |
Duration |
The duration of the function call in microseconds. |
In File (infiledes) |
The input file descriptor. |
In Bytes (inbytes) |
The requested number of bytes to read or write. |
Out File (outfiledes) |
The output file descriptor. |
Out Bytes (outbytes) |
The actual number of bytes read or written. |
Thread ID (tid) |
The thread identifier. |
Stack Depth |
The number of stack frames in use during this function call. |
Record Settings
Click the Record Settings button () in the inspector pane to customize the following recording options.
Sampling Rate
Set how often the instrument records information. The slider allows sampling from 1/10th of a second to 1 second in 1/10 of a second increments. The text field allows for other 1/10th increments. The default value is 1/10th of a second.
System Statistics
Select a statistic to see it graphed in the timeline pane. Click the shape or the color well to change how a statistic is represented.
Select statistics to list
Select the statistics to be displayed in the System Statistics area.
Display Settings
Click the Display Settings button () in the inspector pane to customize the following display settings.
Track Display Settings
These settings control how information is displayed in the timeline pane.
Active Probes
The following active probes display settings are available.
Setting |
Bundled probes |
State |
---|---|---|
File Attributes |
|
On by default. |
File Permissions |
|
On by default. |
Open and Close |
|
On by default. |
Other |
|
Off by default. |
Read and Write |
|
On by default. |
Shared Memory |
|
Off by default. |
Sockets |
|
Off by default. |
Stats |
|
Off by default. |
Call Tree
The following call tree display settings filter the call tree in the detail pane.
Call Tree Constraints
The following options filter the call tree to display calls that fall within a specific threshold based on the settings below.
Data Mining
Allows you to filter through the collected data for specific symbols and libraries.
Detail Pane Columns
Summary Detail Type
The following summary columns are available in the detail pane.
Column name |
Definition |
---|---|
# |
The sequence number. |
Function |
The name of the function being called. |
Duration µs |
The duration of the function call in microseconds. |
In File |
The input file descriptor. |
In Bytes |
The requested number of bytes to read or write. |
Out File |
The output file descriptor. |
Out Bytes |
The actual number of bytes read or written. |
Thread ID |
The thread identifier. |
Stack Depth |
The number of stack frames in use during this function call. |
Error |
The most recent error during the function call. |
Path |
The path to the file on which the executable performed the operation. |
Parameters |
The parameters for the function call. See the API for the specific function for more details. |
Call Tree Detail Type
The following call tree columns are available in the detail pane.
Column name |
Definition |
---|---|
Self % |
The percentage of time the symbol references itself. |
Total % |
The total percentage of time that the symbol is used. |
Library |
The name of the library that generated the call. |
Category |
An icon representing the category of the call. |
Symbol Name |
The name of the symbol being called. |
Graphics Driver Activity Instrument
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