Producers and Consumers

The producers and consumers paradigm is an alternative to Mutex based parallelism where data is instead imagined as a pipeline of operations.

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Example

Instead of a typical Mutex based approach, where each thread modifies the result, where data flow might look like:

graph LR;
A(Start)
B(Thread 1)
C(Thread 2)
D(Thread 3)
E(Thread 4)
F(Output Mutex)

A --> B
A --> C
A --> D
A --> E

B --> F
C --> F
D --> F
E --> F

A producers and consumers approach might look like:

graph LR;
A(Start)
B(Thread 1)
C(Thread 2)
D(Thread 3)
E(Thread 4)
F(Join 1 + 2)
G(Join X + 3)
H(Join X + 4)
I(Output)

A --> B
A --> C
A --> D
A --> E

B --> F
C --> F
F --> G
D --> G
G --> H
E --> H

H --> I

In a real world situation this would be even quicker as we can join all the threads back to the main one and compute the output there i.e. summing the results of the thread calculations.