End-user customers, value-added software suppliers, and the HP sales force frequently ask,
"How many HP 700/RX stations can an HP 9000 Series 800 business server support?"
To answer this key question, this performance brief summarizes tests conducted with a variety of leading software applications, discusses HP 9000 Series 800 system configuration issues, and provides HP 700/RX memory and performance results.
Test Summary
------------
Table 1 summarizes the HP 9000 Model 827S RAM and swap-space usage per HP 700/RX X station for a variety of software applications. The number of HP 700/RX stations supported on a Model 827S is given as a range (e.g. 8 to 15). The first value is application use under a heavy-user profile and the second value is use under a light-user profile. The main findings were:
1. The amount of RAM in the Model 827S limits the number of HP 700/RX
stations supported
2. LAN utilization was not a performance bottleneck.
Network loading does not usually affect user response times with HP 700/RX stations. Application testing showed that when networks persistently exceed 25% utilization, users may begin to notice degradation in interactive response times. This response time may or may not be acceptable. Interactive response time is noticed usually in keyboard entry and/or mouse tracking. As Table 1 indicates, total LAN utilization during application testing was well below 25%. LAN utilization is not a performance bottleneck. To minimize user response times, segment the LAN to keep LAN utilization to less than 25% on an individual segment. Intelligent bridges should be used to create segments with X stations. This will restrict the LAN traffic to only the information meant for individual X stations on that segment.
The network loading guideline can be easily understood by discussing the user transactions executed from an HP 700/RX station: mouse entry, keyboard entry, text display, and graphics display.
Mouse Entry:
Normal mouse movements do not cause LAN traffic except when the pointer is moved through windows or objects on the screen. When a mouse is used to drag or size an object, usually by keeping a button depressed, a large amount of LAN traffic is created. These operations, which create 60 to 90 small packets per second, are usually performed infrequently.
Keyboard Entry:
Each keystroke--key-down, key-up, and transmitting the character to the host--generates three small 100-byte packets.
Text Display:
Text is transmitted efficiently from the host to the X station (1000 characters can be sent to the display in a single packet). Even in cases where pages of text are downloaded, the network load is not likely to be a performance bottleneck.
Graphics Display:
Graphics data can be efficiently transmitted over the network. Typically, 150 to 350 vectors (or lines) are sent in a single data packet. Downloading complex drawings can usually be achieved with 10 to 20 packets. Pixmap downloading requires approximately 1 byte per pixel on the screen. A 500 x 500 pixel picture, which fills approximately half the screen, will require about 25,000 bytes or about 25 packets.
Test System Configuration
-------------------------
The HP 9000 Model 827S was configured with 64 Mbytes of RAM and two 670 Mbyte disk drives, configured with 270 Mbytes of swap space. The operating system was HP-UX version 8.02.
The HP 700/RX was Model 19Ca (19-inch color) X station with 10 Mbytes of RAM. The X server software was version B.03.
Host Loading with X Stations
----------------------------
The number of HP 700/RX stations supported by a specific host system is limited configuration parameters of the host system, including:
1. compute power of the host system (SPECmarks)
2. availability of host system memory (RAM)
3. type of application software
4. intensity of user interaction with the application
5. number of active users.
Host System SPECmarks
---------------------
Based on application performance characterization of CPU usage and end-user feedback, we recommend that you allow from 2-4 SPECmarks per HP 700/RX station user. However, many cases exist in which host CPU usage may be as low as 1 SPECmark per X station user. These are generally situations that involve several terminal emulation windows and simple graphics. If SPECmarks were the sole host loading factor, you would expect an HP 9000 Model 827S with 36 SPECmarks could support anywhere from 3 to 36 HP 700/RX stations, depending on the application and frequency of use. In practice, the range is from 3 to 20 HP 700/RX stations, due to host RAM usage.
Host RAM
--------
The amount of host RAM required for each HP 700/RX station user also depends on the specific application. The availability of host RAM is one of the overall major factors in determining the number of HP 700/RX stations that the host will support. Once host RAM is fully consumed, system performance will begin to degrade rapidly due to demand paging to disk.
System administrators can minimize host RAM use by configuring restricted user access to certain applications. Test results showed that host RAM could be reduced by as much as 25% by using HP-UX 8.02 shared libraries. Many users tend to run one major application, a terminal emulator, a few utility X clients (e.g., xclock, xload), and a window manager. With this mix of applications, 4 to 6 Mbytes of host system RAM per HP 700/RX station user is a good rule of thumb.
If HP VUE is used as the graphical user interface in addition to the application described above, then 6-8 Mbytes of host system RAM for each HP 700/RX station will be required.
For applications where users primarily run a few terminal emulators for
electronic mail or database access, 1 to 2 Mbytes of host system RAM,
per HP 700/RX station, will likely be sufficient.
User Interaction with Applications
----------------------------------
User interaction with an application is another key factor in determining the number of HP 700/RX stations that a specific host system will support. The duration and intensity of keyboard entry and mouse tracking may have a direct impact on the quality of interactive performance.
HP 700/RX RAM Usage
-------------------
Some customers assume that X stations need to be configured with the same amount of local memory as workstations. The HP 700/RX stations do not need vast amounts of local RAM to work well. The standard base memory of 4 Mbytes included with all HP 700/RX stations will meet many users' requirements.
HP 700/RX stations support up to a maximum of 18 Mbytes of DRAM. We expect customers to need more than the standard 4 Mbytes of memory under the following conditions:
1. large and numerous graphic files that contain bitmaps displayed
simultaneously
2. the application makes extensive use of widgets and windows
3. the backing-store feature is used frequently to store and redraw
overlaid windows
4. the application requires Asian fonts.
HP 700/RX Performance
---------------------
HP 700/RX stations deliver interactive X Window performance that compares to entry-level workstations configured as an X-server. They have been designed using an Intel i960CA superscalar RISC processor.
The following performance data summarizes the results of tests conducted using xbench, the de facto standard benchmark for measuring X-server performance.
Refer to the October 21, 1991 PC Week article reprint entitled "HP 700/RX Blows Away X Terminal Rivals." This article benchmarked the performance of leading X terminal products. The results of the tests, shown below, clearly position the HP 700/RX station as the industry performance leader. PC Week also tested the X Window performance of a SUN SPARCstation IPC as part of the article review. The HP 700/RX clearly outperformed the IPC!
Xstone Ratings for HP 700/RX Models
-------------------------------------
| HP 700/RX Model Xstones* |
=====================================
| Mi (mono base) 90,000 |
| Ci (color base) 52,000 |
| Ca (color/gray base) 93,000 |
| |
| 19Ga (19" greyscale) 93,000 |
| 19Mi (19" mono) 90,000 |
| 14Ci (14" color) 52,000 |
| 15Ci (15" color) 52,000 |
| 17Ci (17"color) 52,000 |
| 17Ca (17"color) 93,000 |
| 19Ca (19"color) 93,000 |
| 19Cs (19"color Sony) 93,000 |
-------------------------------------
* Xstone ratings are based on the B.04 version of the HP 700/RX
software.
Conclusions and Recommendations
-------------------------------
Use the following "rules of thumb" as basic guidelines towards configuring optimal system solutions that include an HP 9000 Series 800 as the host for HP 700/RX stations:
1. Allow 2 to 4 host system SPECmarks per HP 700/RX station
2. Configure the host system RAM as follows:
a. for terminal-emulator based applications, 1 to 2 Mbytes per HP
700/RX station
b. for X-based applications, 4 to 6 Mbytes of RAM per HP 700/RX
station
c. if using HP VUE, 6 to 8 Mbytes of RAM per HP 700/RX.
3. Configure color HP 700/RX stations with 4 to 6 Mbytes of RAM. The
standard 4 Mbytes of RAM included in the HP 700/RX Model 19Mi (19"
monochrome) station will normally be sufficient.
4. Segment the LAN if total LAN utilization will exceed 25%. Typically
40 to 50 nodes can exist on each segment.
5. To add HP 700/RX stations to an existing system, use HP-UX
monitoring tools (HP Glance, monitor) to characterize the system
performance during application use to determine and quantify if
additional RAM or SPECmarks are required to support the additional
work load.
Disclaimer
----------
The information contained in this performance and configuration brief is simply meant to give you basic guidelines for configuring system solutions. Test results are highly dependent on user profiles and system configurations and have not been verified to the extent to guarantee accuracy. Hewlett-Packard Company specifically disclaims any and all warranties, expressed or implied, including but not limited to the warranties of merchantability or fitness for a particular purpose with respect to the information in this document. The information presented is subject to change without notice.
