HP Virtual Server Environment: Tips for Application Developers

activated (for example 16 cores in this example). Record the performance level when all the

resources have been activated.

 Run the procedure in reverse. Measure performance on a small static system (i.e. 4 cores in

the example above), then measure performance on a system that starts large (16 cores) and

scales down to the small size (4 cores).

 Compare the results. An ideal application will deliver the same performance level in the

dynamic VSE environment as in the static environment. Applications that sense their

environment at startup and limit their work capacity (number of threads, size of data

structures, etc) may not reach the full performance when resources scale as they do when the

resources are statically allocated. Similarly some applications may not perform as well when

initialized in a large environment then scaled down.

Many applications flex with no issues. Many applications flex well within the range needed in a

production environment. For example, an application may not flex well going from a one core

environment to a 64 core environment, but may flex just fine within a range from 4 cores to 16 cores.

Applications that use large numbers of threads or processes (relative to the number of cores available)

tend to flex very well. Environments that use FSS based resource partitions tend to flex very well.

Environments that involve multiple applications, or multiple separate instances of an application tend

to flex very well.

Packard Development Company, L.P. The information contained

herein is subject to change without notice. The only warranties for HP products and

services are set forth in the express warranty statements accompanying such

products and services. Nothing herein should be construed as constituting an

additional warranty. HP shall not be liable for technical or editorial errors or

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Linux is a U.S. registered trademark of Linus Torvalds. Microsoft and Windows are

U.S. registered trademarks of Microsoft Corporation. UNIX is a registered

trademark of The Open Group.

4AA0-xxxxENW, May 2006