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| Rev | Author | Line No. | Line |
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| 1663 | pj | 1 | VALUE SCHEDULER SUITE |
| 2 | --------------------- |
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| 3 | |||
| 4 | by Paolo Gai 2001 |
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| 5 | |||
| 6 | --------------------- |
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| 7 | |||
| 8 | NOTE (2004/07/05): This version of crunch WAS working with an old version of |
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| 9 | shark. it should not be too difficult to make it working on the new |
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| 10 | versions. But be aware that the Scheduling Modules interface has |
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| 11 | changed... |
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| 12 | |||
| 13 | --------------------- |
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| 14 | |||
| 15 | This is a set of programs I wrote for the assignments in the Malardalens |
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| 16 | University, Sweden. |
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| 17 | |||
| 18 | The assignment for the students was the creation of a value scheduler that |
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| 19 | can handle overload. |
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| 20 | |||
| 21 | --------------------------------------------------------------------------- |
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| 22 | |||
| 23 | Directories: |
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| 24 | |||
| 25 | - This directoty should contain only this file and a makefile that should |
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| 26 | help in the creation of the applications. |
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| 27 | |||
| 28 | - The LOAD directory contains a little application that can be used to |
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| 29 | generate some random load composed by a set of HARD and VALUE tasks with |
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| 30 | different execution time. |
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| 31 | |||
| 32 | - The CRUNCH directory contains all the source code of the value schedulers |
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| 33 | done by me and by the students, plus an application called CRUNCH used |
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| 34 | to test the performance of the schedulers. |
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| 35 | |||
| 36 | - The OUT directory contains all the compiled CRUNCH applications. |
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| 37 | Every bynary image contains the CRUNCH application configured with |
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| 38 | different scheduling algorithms. |
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| 39 | |||
| 40 | --------------------------------------------------------------------------- |
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| 41 | |||
| 42 | LOAD GENERATION |
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| 43 | |||
| 44 | The load generation produces a .dat file suited for the CRUNCH |
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| 45 | application. The produced file contains a set of hard periodic tasks and |
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| 46 | a set of value tasks. |
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| 47 | |||
| 48 | The load generation can be tuned in various ways, and a set of small |
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| 49 | C programs are provided to step-by-step generate the load. |
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| 50 | |||
| 51 | Start: Length of the load pattern |
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| 52 | --------------------------------- |
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| 53 | First, we need the length of the load pattern. This information has |
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| 54 | to be given in the LENGTH.DAT configuration file (that file contains only |
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| 55 | the number of seconds that the load should cope. |
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| 56 | |||
| 57 | Step 1: Generation of the Shape of the hard periodic load |
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| 58 | --------------------------------------------------------- |
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| 59 | Given the LENGTH.DAT file, we need to produce a random shape for the |
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| 60 | Periodic load. |
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| 61 | |||
| 62 | The random shape is the limit of bandwith that a certain time can be |
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| 63 | available for creating hard tasks. Hard task creation is disabled |
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| 64 | if the currently used bandwidth is higher than the limit. |
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| 65 | |||
| 66 | The random shape is contained into the SHAPE.DAT file. The file contains |
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| 67 | a sequence of numbers in the form: <time> <b>, |
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| 68 | where <time> is the time in seconds to wich refers the threshold, |
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| 69 | and <b> is the maximum bandwidth that can be used after <time>. |
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| 70 | The data is ordered by time. |
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| 71 | |||
| 72 | Step 2: Generation of the Hard Task pattern |
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| 73 | ------------------------------------------- |
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| 74 | Given the Shape of the pattern to be created, a small application |
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| 75 | really generates the load that will be handled by the CRUNCH application. |
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| 76 | The output of this phase is contained into the file HPATTERN.DAT. |
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| 77 | |||
| 78 | Step 3: Generation of the Value pattern |
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| 79 | --------------------------------------- |
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| 80 | Starting from the informations contained into the SHAPE.DAT, step 3 |
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| 81 | produces an aperiodic load. |
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| 82 | |||
| 83 | The load is formed by a set of different tasks with different wcets and |
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| 84 | dline. |
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| 85 | |||
| 86 | a first set (called random) is really random with random periods and wcets |
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| 87 | |||
| 88 | a second set (called bad) creates a set of big tasks with long dline and |
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| 89 | a set of tasks with short dline, similar to the pattern used by Baruah |
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| 90 | (in any case it remains offline. |
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| 91 | |||
| 92 | Step 4: Creation of the file for the value scheduler |
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| 93 | ---------------------------------------------------- |
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| 94 | Finally, the step4 takes as imput the outputs from step3 and step2 toi create |
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| 95 | the initialization file for crunch... |