CDE and Performance

   

HP-UX Virtual Partitions
By Marty Poniatowski

Table of Contents
Chapter 14.  Common Desktop Environment


CDE isn't a monolithic application; it's a set of components layered on top of the operating system, the X Window System, and Motif. Each underlying layer takes its share of RAM before CDE or any other client even starts. Because of the low-level nature of these layers, the RAM they use is hardly ever regained through swapping to disk.

In some cases, operating system overhead and user application requirements restrict the amount of RAM available for a graphical user interface to little more than enough to run a window manager such as Motif. Because the CDE workspace manager and the Motif window manager take roughly the same amount of RAM, users can enjoy an enriched graphical environment with the added value of CDE's multiple workspaces at essentially no extra RAM cost over running the Motif window manager.

Tactics for Better Performance

Unless all your users have RAM-loaded powerhouses for systems, you will need to spend some time developing a performance strategy. If you conceive of performance as a bell-shaped curve, satisfaction lies on the leading edge. Your performance strategy should do everything it can to keep your users on the leading edge.

Probably the most logical approach is to start small and grow. In other words, start out with minimal user environments on all the systems on your network. Gradually add software components until you or your users begin to notice performance degradation. Then back off a little. Such an approach might take several weeks or more to evaluate, as you add components and as your users spend several days actually working in the environment to determine the effect of your changes on system performance and their frustration levels.

The most RAM-expensive pieces of CDE are the workspace manager, the session manager, and the file manager. The workspace manager is expensive because portions of it are always in RAM (assuming that you are moving windows around and switching workspaces). The CDE workspace manager is no more expensive than the Motif window manager; if you want a GUI, it's just a price you have to pay. The session manager is expensive only during logout and login, as it saves and restores sessions. The rest of the time, the session manager is dormant and gets swapped out of RAM. Saving your current work session is nice at the end of the day, but it's something to consider giving up if you want to improve your login and logout performance. The file manager is expensive because it wakes up periodically and jumps into RAM to check the status of the file system and update its file manager windows. When it jumps into RAM, it pushes something else out, for example, maybe the desktop publishing program you're using.

Here are some other ideas that you may find useful:

Terminal Emulators

xterms are a little less RAM-expensive than dtterms. Unless you need the block mode functionality of a dtterm, xterm might be a better choice for terminal emulation.

Automatic Saves

Some applications automatically save data at periodic intervals. Although this feature can be beneficial, you need to evaluate its effect in light of performance. If the application is central to your users' work, fine, but if not, you might want to disable the automatic save feature.

Scroll Buffers

Large scroll buffers in terminal emulators can be a real convenience, but they can also take up a lot of RAM. Even modestly sized scroll buffers, when multiplied by three or four terminal emulators, consume a lot of RAM.

Background Bitmaps

Avoid large bitmaps; they increase the X server size. Especially avoid switching large bitmaps frequently within a session. If you are hunting for a new background, be sure to restart the X server after you've found the one you want and have included it in the proper sessionetc file. The most efficient bitmaps are small ones that can be repeated to tile the background.

Front Panel

Reconfigure the front panel to minimize the number of buttons. Keep just enough to meet user needs. This tactic decreases the workspace manager size in RAM and speeds login and logout.

Pathnames

Whenever possible, use absolute pathnames for bitmap specifications. Although this approach decreases the flexibility of the system, it speeds access time.


       
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    HP-UX Virtual Partitions
    HP-UX Virtual Partitions
    ISBN: 0130352128
    EAN: 2147483647
    Year: 2002
    Pages: 181

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