OS/2 Warp FAQ List (20 Feb 95) Section 0507

(5.7) Measuring Performance and Memory Usage

How do I measure OS/2 Warp performance and memory usage?

OS/2 Warp does not treat system resources like DOS. Memory is treated as a virtual resource, used intelligently. For example, OS/2 Warp will retain unused, "dormant" code in memory if that memory is not otherwise required, on the assumption that that code may be used again. Also, all but a small portion of OS/2 Warp (and most applications, no matter how many are running) may be paged to disk should a large amount of physical memory be required. Utilities which display "free" memory, then, are only useful for rough, relative measurements. (Such utilities also often fail for another reason: many only report the largest contiguous block of free physical RAM. And a few will never report more than 16 MB of RAM because they were designed for OS/2 1.x.)

Similarly, utilities which purport to measure system load (e.g. Pulse) should not be relied upon for definitive performance measurement. Subjective assessments are often much more reliable. Pulse (and similar utilities) rely on a measurement of processor time allocated to a thread running at OS/2 Warp's lowest priority. This method is sometimes subject to erroneous results.

That said, more rigorous system performance optimization and monitoring tools include IBM's System Performance Monitor/2, BenchTech (Synetik, phone 303-241-1718), OR/SysMon (International OS/2 User Group, phone +44-285-641175 or FAX +44-285-640181), CPU Monitor (BonAmi), and Performance 3.0 (Clear & Simple, phone 203-658-1204).

Note that OS/2 Warp's swap file is designed to behave with hysteresis. It will not shrink in size as easily as it grows, under the assumption that swap space needed once may be needed again. It should shrink given enough time and continued, less intense system loads.

Related information:

(5.6) Performance Tuning

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