Buffers

Article
10/29/2021

Describes either the number of buffers to be allocated when starting a session or the percentage of total memory to be allocated for the session, depending on the value of the PercentageOfTotalMemory attribute.

Element Hierarchy

<WindowsPerformanceRecorder>
- <Profiles>
  - <SystemCollector>
    - <Buffers>
  - <EventCollector>
    - <Buffers>
  - <HeapEventCollector>
    - <Buffers>
  - <Profile>
    - <Collectors>
      - <SystemCollectorId>
        
        <Buffers>
      - <EventCollectorId>
        
        <Buffers>
      - <HeapEventCollectorId>
        
        <Buffers>

Syntax

<Buffers Operation               = "Set" | "Add" | “Remove”
         Value                   = unsignedLong
         PercentageOfTotalMemory = Boolean
         MaximumBufferSpace      = unsignedLong >
</Buffers>

Attributes and Elements

Attributes

Attribute	Description	Data type	Required	Default
MaximumBufferSpace	Indicates the maximum size of the buffer, in megabytes, that will be used for collection. This value only applies when PercentageOfTotalMemory is `true`.	unsignedLong	No
Operation	Indicates whether buffers should be set or added.	This attribute can have one of the following values: Set Add Remove	No	Set
PercentageOfTotalMemory	When set to `true`, limits the amount of memory that can be consumed to the value of Value.	Boolean	No	false
Value	Indicates the number of buffers, or if PercentageOfTotalMemory is set to `true`, the percentage of memory for the buffers.	unsignedLong	Yes

Child Elements

None.

Parent Elements

Element	Description
EventCollector	Represents an event collector.
EventCollectorId	Represents an event collector identifier.
HeapEventCollector	Represents a heap event collector.
HeapEventCollectorId	Represents a heap event collector identifier.
SystemCollector	Represents a system collector.
SystemCollectorId	Represents a system collector identifier.

Remarks

This element is used only for in-memory capture.

Example

The following examples show how this element is used in system collector and event collector definitions.

The first example sets the buffer size to 512 KB and limits the total amount of memory consumed to 3 percent. The second example sets 64 buffers of 128 KB each.

<SystemCollector
  Id="WPRSystemCollector"
  Name="NT Kernel Logger"
  FileName="WPRKernel.etl">
  <BufferSize
    Value="512"/> 
  <Buffers
    Value="3"
    PercentageOfTotalMemory="true"/>
</SystemCollector>

<EventCollector
  Id="WPREventCollector"
  Name="WPR Event Collector"
  FileName="somefilename.etl">
  <BufferSize
    Value="128"/>
  <Buffers
    Value="64"/>
</EventCollector>