Performance Issues

Agenda

• Partitioning for performance
• Data access and communication
• Summary
• Goal is to understand simple trade-offs involved in writing a parallel program keeping an eye on parallel performance
  • Getting good performance out of a multiprocessor is difficult
  • Programmers need to be careful
  • A little carelessness may lead to extremely poor performance

Partitioning For Perf .

• Partitioning plays an important role in the parallel performance
  • This is where you essentially determine the tasks
• A good partitioning should practise
  • Load balance
  • Minimal communication
• Low overhead to determine and manage task assignment (sometimes called extra work)
• A well-balanced parallel program automatically has low barrier or point-to-point synchronization time
  • Ideally I want all the threads to arrive at a barrier at the same time