HP-UX Programming Tools Release Notes

34 Chapter4
Problem Descriptions and Fixes
Problems and Limitations
HP PAK Puma Limitations Regarding Next Run of a
Program
When using Puma to attach to the next run of a target program, be
aware of the following limitations:
• If you specify a relative path for your target program's name in the
Choose Target Program window, Puma assumes that path is relative
to the directory from which you invoked Puma. If this assumption is
wrong and you invoke your program from some other directory, Puma
may fail to attach to your program and may even fail to notice that
your program has begun execution.
• If Puma attaches to a target program that terminates too quickly,
Puma may not be able to collect data. You may see error messages
similar to the following:
?(PUMA) Failed first poll to attached process.
?(PUMA) MONITOR command failed
The target must run for at least a few seconds in order for Puma to
collect data on it.
HP PAK Puma Problem with Signal Blocking and
Multiple Threads
Any situation in a multi-threaded program that blocks the receiving of
signals will distort Puma’s sampling interval, resulting in deceptive
spikes of resource usage. While the total resource usage will be correct,
the actual time between samples will be longer than the expected
interval.
Some situations where signal reception will be blocked include:
• During loading of shared libraries by the dynamic loader (see
dld.sl(5))
• During calls to sigprocmask(2)
To determine whether high resource use is really a performance problem
or just the result of signal blockage, examine the change in system and
user cycles during the sample interval.