[d67cdb7] | 1 | % ====================================================================== |
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| 2 | % ====================================================================== |
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| 3 | \chapter{Putting it all together} |
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| 4 | % ====================================================================== |
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| 5 | % ====================================================================== |
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| 6 | |
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| 7 | |
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| 8 | \section{Threads as monitors} |
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[3364962] | 9 | As it was subtely alluded in section \ref{threads}, \code{threads} in \CFA are in fact monitors. This means that all the monitors features are available when using threads. For example, here is a very simple two thread pipeline that could be used for a simulator of a game engine : |
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[d67cdb7] | 10 | \begin{cfacode} |
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| 11 | // Visualization declaration |
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| 12 | thread Renderer {} renderer; |
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| 13 | Frame * simulate( Simulator & this ); |
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| 14 | |
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| 15 | // Simulation declaration |
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| 16 | thread Simulator{} simulator; |
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| 17 | void render( Renderer & this ); |
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| 18 | |
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| 19 | // Blocking call used as communication |
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| 20 | void draw( Renderer & mutex this, Frame * frame ); |
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| 21 | |
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| 22 | // Simualation loop |
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| 23 | void main( Simulator & this ) { |
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| 24 | while( true ) { |
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| 25 | Frame * frame = simulate( this ); |
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| 26 | draw( renderer, frame ); |
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| 27 | } |
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| 28 | } |
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| 29 | |
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| 30 | // Rendering loop |
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| 31 | void main( Renderer & this ) { |
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| 32 | while( true ) { |
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| 33 | waitfor( draw, this ); |
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| 34 | render( this ); |
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| 35 | } |
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| 36 | } |
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| 37 | \end{cfacode} |
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| 38 | One of the obvious complaints of the previous code snippet (other than its toy-like simplicity) is that it does not handle exit conditions and just goes on for ever. Luckily, the monitor semantics can also be used to clearly enforce a shutdown order in a concise manner : |
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| 39 | \begin{cfacode} |
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| 40 | // Visualization declaration |
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| 41 | thread Renderer {} renderer; |
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| 42 | Frame * simulate( Simulator & this ); |
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| 43 | |
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| 44 | // Simulation declaration |
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| 45 | thread Simulator{} simulator; |
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| 46 | void render( Renderer & this ); |
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| 47 | |
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| 48 | // Blocking call used as communication |
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| 49 | void draw( Renderer & mutex this, Frame * frame ); |
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| 50 | |
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| 51 | // Simualation loop |
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| 52 | void main( Simulator & this ) { |
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| 53 | while( true ) { |
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| 54 | Frame * frame = simulate( this ); |
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| 55 | draw( renderer, frame ); |
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| 56 | |
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| 57 | // Exit main loop after the last frame |
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| 58 | if( frame->is_last ) break; |
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| 59 | } |
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| 60 | } |
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| 61 | |
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| 62 | // Rendering loop |
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| 63 | void main( Renderer & this ) { |
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| 64 | while( true ) { |
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| 65 | waitfor( draw, this ); |
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| 66 | or waitfor( ^?{}, this ) { |
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| 67 | // Add an exit condition |
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| 68 | break; |
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| 69 | } |
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| 70 | |
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| 71 | render( this ); |
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| 72 | } |
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| 73 | } |
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| 74 | \end{cfacode} |
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| 75 | |
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| 76 | \section{Fibers \& Threads} |
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