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- FILE: OSDAPERF.FAX - 5/11/94
-
- TITLE: 940511 OS/2 2.x CPU PERFORMANCE FOR DOS APPLICATIONS
- RUNNING IN A MULTITASKING VIRTUAL DOS MACHINE
- (VDM) ENVIRONMENT
-
- DESCRIPTION OF SYMPTONS:
- DOS APPLICATIONS PERFORMING SLOW IN A VDM
-
- SUMMARY OF RESOLUTION:
-
- There is only one CPU in the computer. When the CPU
- processes for one program you will get maximum performance.
- When you have that same CPU doing many other tasks at the same
- time as doing the dedicated process, you can expect a
- performance degradation. It is the same CPU now doing many
- more things other than the one thing it was doing before,
- therefore, there will be slower speed.
-
- VDMs do not offer CPU acceleration and OS/2 does not
- accelerate your CPU. OS/2 utilizes the idle time of your CPU
- much better and allows for users to continue working on other
- things while a spreadsheet calculates, thus allowing customers
- to use their computer, while under DOS that computer would be
- tied up doing the calculation and not usable. If VDM
- priorities were able to be increased in a future release of
- OS/2, then the customer could allocate more processing time to
- the spreadsheet session.
-
- Hopefully, in a future release of OS/2, there will be a
- DOS-SETTING that allows setting of VDM priorities by the
- customer instead of hard coded by the operating system. Even
- at that time, the CPU will still be doing some other things in
- the background, but performance for that DOS session will be
- increased.
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- Report by: OS/2 Dosap Analyst Team - 05/94
- IBM - Boca Raton, Florida
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