User manual

The PCoIP image cache captures spatial, as well as temporal, redundancy. For example, when you scroll
down through a PDF document, new content appears from the bottom of the window and the oldest content
disappears from the top of the window. All the other content remains constant and moves upward. The
PCoIP image cache is capable of detecting this spatial and temporal redundancy.
Because during scrolling, the display information sent to the client device is primarily a sequence of cache
indices, using the image cache saves a significant amount of bandwidth. This efficient scrolling has benefits
both on the LAN and over the WAN.
n
On the LAN, where bandwidth is relatively unconstrained, using client-side image caching delivers
significant bandwidth savings.
n
Over the WAN, to stay within the available bandwidth constraints, scrolling performance is often
degraded unless client-side caching is used. In this situation, client-side caching can save bandwidth
and ensure a smooth, highly responsive scrolling experience.
By default this feature is enabled, so that the client stores portions of the display that were previously
transmitted. The default cache size is 250MB. You can configure the client image cache size, from a
minimum of 50MB to a maximum of 1024MB for View Client 1.7 and later versions. The maximum size for
earlier versions is 300MB. A larger cache size reduces bandwidth usage but requires more memory on the
client. A smaller cache size requires more bandwidth usage. For example, a thin client with little memory
requires a smaller cache size.
Setting the Configuration Property
To configure the cache size, you can set the pcoip.image_cache_size_mb property. For example, the
following setting configures the cache size to be 50MB:
pcoip.image_cache_size_mb = 50
Use a space before and after the equals (=) sign. If you specify a number less than 50, the number is
converted to 50. If you specify a number larger than the maximum, the number is converted to maximum.
You can set this property in any of several files. When View Client starts up, the setting is processed from
various locations in the following order:
1 /etc/teradici/pcoip_admin_defaults.conf
2 ~/.pcoip.rc
3 /etc/teradici/pcoip_admin.conf
If a setting is defined in multiple locations, the value that is used is the value from the last file read.
NOTE You can set the following property to display a visual indication that the image cache is working:
pcoip.show_image_cache_hits = 1
With this configuration, for every tile (32 x 32 pixels) in an image that comes from the image cache, you can
see a rectangle around the tile.
Using VMware Horizon View Client for Linux
34 VMware, Inc.