1. 3.8 static vs dynamic thread management
QT provides a pool of threads, applications gain performance by reusing threads
When a thread is needed, an idle thread is selected from the pool
This is more efficient even though thread creation is orders of magnitude faster than process creation, thread creation still takes time.
Example listing 3.25

2. Creating and Managing a pool of threads
REQUIREMENTS
Be able to describe computational tasks
Communicate computational tasks
Identify threads that are executing a task
Signal the termination of a task’s execution

3. 3.9Debugging Multithreaded Applications
GDB and DDD (data display debugger, a front end to GDB or DBX)
Compile with –g
Often time sensitive affected by the debugger

4. Steps to ensure bug free applications
Don’t introduce bugs
Write bug free code
Use a good design
Use previously written programs adapted to specific application
Create a log of programs execution
Allow the threads to be variable
Debugging 1 thread is easier than 10, 2 or 3 also easier

5. Printf or Cout Typically not sufficient
Output is intermixed via the threads
Can write to a file
myprog 2> trace.log
Use a high resolution timer to time stamp messages
#define DEBUG
#ifdef DEBUG
………
#endif

6. More debugging hints Disable compiler optimizations
An optimization can (rarely) introduce bugs

7. Many example programs
Qthreads
Openmp
MPI
GPU