By default the VMware View PCoIP protocol dynamically optimizes for the best user experience for the given resource constraints. In the majority of environments, this is the desired approach. However, there can be times where individual users or group administrators are interested in different resource utilization policies and in past blogs and whitepapers we have discussed in detail how to configure PCoIP to optimize for constrained resource consumption. In this post, I just wanted to provide a concise summary of these recommendations by highlighting 4 simple optimizations that our extensive internal testing has shown yield significant benefits:
- Disable build-to-lossless: setting enable_build_to_lossless to 0 delivers about a 1.3X reduction in bandwidth for typical office workloads. And, PCoIP still builds to a high quality lossy image that is virtually indistinguishable from fully lossless for office workloads.
- Optimize video frame-rate: setting maximum_frame_rate to 15 reduces video bandwidth by almost 1.7X in many situations, yet continues to deliver a smooth motion experience.
- Optimize audio bandwidth: setting audio_bandwidth_limit to 100 reduces audio bandwidth by around 5X, while continuing to deliver good quality sound.
- In-guest optimization: setting Windows visual settings to "optimize for performance" reduces bandwidth by over 1.1X for typical office workloads. Additionally, disabling ClearType reduces bandwidth by a further 1.05X. Disabling desktop wallpaper, and setting the screen saver to none, can also deliver bandwidth savings, although the new client image caching support in View 5 often significantly reduces the additional bandwidth traditionally associated with these options. Finally, disabling Windows update, Super-fetch and Windows index significantly reduces redo-log growth, minimizing storage requirements. Full details of in-guest optimizations can be found here.
[N.B. the PCoIP settings can be set via the Windows registry, or via GPO.]
These simple changes significantly decrease bandwidth consumption, increase consolidation ratios, have minimal impact on typical user experiences and represent good defaults in many environments.
At the recent VMworld we mentioned that VMware View 5 introduces PCoIP support for client-side image caching. In our VMworld presentation, we highlighted that, on average, this caching optimization reduces bandwidth consumption by about 30%. However, there are a number of important scenarios where the ability of the PCoIP image cache to capture spatial, as well as temporal, redundancy delivers even bigger benefits.
For instance, consider scrolling through a PDF document. As we scroll down, new content appears along the bottom edge of the window, and the oldest content disappears from the top edge. All the other content in the application window remains essentially constant, merely shifted upward. The PCoIP image cache is capable of detecting this spatial and temporal redundancy. As a result, for scrolling operations, the display information sent to the client device is primarily just a sequence of cache indices — delivering significant bandwidth savings.
This efficient scrolling has a couple of key benefits;
- On LAN networks, where bandwidth is relatively unconstrained, there’s sufficient bandwidth available for high quality scrolling even when client-side caching is disabled. In these situations, enabling client-side image caching delivers significant bandwidth savings – experimenting with a variety of different applications and content types (text heavy, image heavy etc), I'm seeing bandwidth reductions of over 4X (compared with caching disabled. mileage may vary, but I’m seeing this fairly consistently)!
- On WAN networks, where bandwidth is fairly scarce, when client-side caching is disabled, scrolling performance is often degraded to stay within the available bandwidth. In these situations, in addition to bandwidth reductions (which vary based on the degree to which scrolling performance is degraded when client-side caching is disabled), client-side caching also ensures smooth, highly responsive scrolling operations even in WAN environments with very constrained bandwidth.
Slides from our recent VMworld presentation on View 5 PCoIP performance (EUC1987) are now available here. In addition to discusing the latest PCoIP optimizations and best practices in detail, it also presents competitive data.