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GPUView GPU hardware queue

This article describes what the user views when looking at the GPU Hardware Queue with GPUView. This first diagram is a simple zoomed-in view of the GPU Hardware Queue.

Zoomed-in view of a GPU Hardware Queue.

The GPU Hardware Queue represents workflow on the hardware. In these workflow queues, the item on the bottom of the stack of rectangles represents the work that is currently executing. The rectangles stacked above it represent work that is in waiting.

Diagram showing workflow queues with rectangles representing work in progress and waiting.

In the preceding diagram:

  • The DMA packet in the red ellipse represents the work that the hardware was executing.
  • The DMA packet in the black ellipse represents the second packet of two that the video scheduler placed down on the hardware. They're packets in waiting.

Diagram illustrating the transition of DMA packets in the GPU Hardware Queue.

Notice that the end of a rectangle doesn't mean the end of the functional lifetime of the object. Here, inside the red ellipse, when the hardware finished with the present packet (item on the bottom), the DMA packet in waiting now transitions into the DMA packet that the hardware is processing. At this transition point, the topmost DMA packet in waiting advances (down) one step closer to actually running on the hardware.

Zooming out slightly and left-selecting the top DMA packet produces the following diagram.

Diagram of a selected DMA packet with three transitional points in the GPU Hardware Queue.

This DMA packet was selected by left-clicking it. Notice that the packet has three transitional points while it is in the queue. The entire time span of this object is considered time in the hardware queue, but only the last section (rightmost where it is on the bottom of the stack) is counted as execution time on the hardware.

The color coding is also important. The color for each DMA packet corresponds to a particular Context CPU Queue in a particular Process.

Diagram showing the association between DMA packets and Context CPU Queue in a Process.

Zooming out a little from the previous diagram, the associated process is (6584) SchBillboard.exe. It has the matching color and matching selection in process Context CPU Queue.

There's also the text in the upper right-hand corner of the GPU Hardware Queue area. It can be seen in the following diagram.

Screenshot of text in the upper right-hand corner of the GPU Hardware Queue area.

The first item is the count of DMA packets that received execution time on the hardware. The second value is the time of these executing packets. The third is the percentage of the viewport area where DMA packets were executing on the hardware.

Types of DMA Packets

Four types of DMA packets are found in the GPU Hardware Queue.

Diagram displaying four types of DMA packets found in the GPU Hardware Queue.

The most common are Standard DMA Packets and Present Packets. Both of these packets represent client requests on the hardware.

The two types of DMA packets that are less common are Paging Packets and Preemption Packets. Paging Packets are always red and Preemption Packets are always black. Both these packets are placed in the GPU Hardware Queue on behalf of the video scheduler. Paging Packets occur when data needed for processing needs to be prefetched. Preemption Packets are generated when the scheduler determines that it needs to abort the current work flow to provide some higher-priority content.

Selectable Areas

All DMA Packets are selectable via the left mouse button. All selectable items show this capability through changing the mouse pointer into the hand icon. When a DMA Packet is selected, the Object Details dialog is launched containing information about the particular DMA packet selected.