Reasons to Thread (time)

• Increase concurrency to overcome I/O latency

• Increase concurrency to use multiple CPUs

• Replace control loops for program clarity

• Use threads to keep User Interface response times down

• Exploit `parallel slackness’ to keep system busy

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EXAMPLE: Browsers use multiple TCP/IP connections to overcome 3xRTT (approx) setup latency; UNIX directory scanning algorithms can run many times faster even within one partition allowing better queueing of disk activity in OS (done in C/C++/Java).

CHECKLIST:

• What is/are your main reason(s) for threading?

• Can you test results of your tinkering on your target system?

• Do you have multiple targets to optimise for some combination of?

• Remember that threading an algorithm will almost always consume some extra time and space and increase complexity.