HP Scalable Visualization Array Software - Manual (Page 13)

Displays
The SVA supports a wide range of displays and configurations, including single displays, tiled displays in
walls, and immersive CAVE environments. The SVA relies on the display capabilities of the graphics cards
in the display nodes. This means that the SVA lets you use whatever display devices are supported by the
graphics card.
Depending on the demands of the display devices, you can use digital or analog output. The aggregate
resolution of these displays can range from 10s to 100s of megapixels.
The SVA supports up to eight display nodes
1
in a Display Surface. The display nodes in your cluster can
drive one or two display devices in the case of xw8200 nodes, and one to four display devices in the case
of xw9300 nodes. This means that you can drive a maximum of 32 display devices using eight xw9300s.
See the
SVA System Administration Guide for more information on setting up and cabling display nodes,
display devices, and Display Surfaces.
SVA Functional Attributes
The key to SVA scalability and flexibility is its combination of cluster technology with high-speed graphics
cards and networks to transfer data. The SVA enables scaling up the number of nodes working on a problem
in parallel to handle larger dataset sizes, to increase frame rates, and to display at higher image resolutions.
Scalability
There are a number of ways that applications can be designed and implemented to take advantage of an
SVA for effective scaling:
•
Performance scaling: Render image data on separate nodes in the SVA. In effect, the work is divided
up among nodes working in parallel. Larger datasets can be accommodated by more render nodes.
The system design can scale from four to forty visualization nodes. This count does not include the
required head node.
The parallel attributes of the rendering pipeline removes a key performance bottleneck of a conventional
hardware accelerated graphics architecture, which feeds data sequentially to a centralized pipeline.
In addition, the choice of a network that transmits data among the visualization nodes with adequately
low latency and high speed maintains interactive frame rates for delivery to the display devices.
•
Resolution scaling: Parallel rendering, combined with the parallel display of multiple tiles makes such
scaling possible. You can display high-resolution data and use large display surfaces, including immersive
displays and display walls.
In general, adding nodes to a dataset of fixed size provides good scaling up of the frame rate, although
speed-up is not linear because of the inevitable overhead due to portions of an application's code that cannot
be made parallel. However, a strength of SVA as a cluster visualization platform is that scalability is nearly
linear when the dataset size and node count are both increased. For example, doubling the node count
from four to eight makes it possible to double the distributed dataset size with virtually no loss of frame rate.
To achieve such gains in frame rate, an application must be a true parallel application to efficiently distribute
data and to load balance across cluster nodes.
Flexibility
One of the most powerful attributes of the SVA is its flexibility, which makes it possible to apply the SVA
effectively to a wide range of technical problems. This flexibility derives from the architectural characteristics
of the SVA.
When the architectural characteristics of the SVA are integrated with an HP high performance compute
cluster (see
Figure 1-1 ), you can select an optimal number of application or compute nodes and match them
with an appropriate number of render and display nodes. Visual applications with high computation
requirements can be distributed over the compute nodes and the visualization nodes; thus the render nodes
can double as compute nodes.
This flexibility is critical because visualization applications often need to perform intensive computations to
compute isosurfaces, streamlines, or particle traces. You can select application nodes based on factors such
1. More display nodes may be supported on an exceptional basis.
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