OS/2 Warp FAQ List (20 Feb 95)

(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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