47 lines
1.4 KiB
ReStructuredText
47 lines
1.4 KiB
ReStructuredText
.. _smp_pi:
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SMP Pi
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###########
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Overview
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********
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This sample application calculates Pi independently in many threads, and
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demonstrates the benefit of multiple execution units (CPU cores)
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when compute-intensive tasks can be run in parallel, with
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no cross-dependencies or shared resources.
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By changing the value of CONFIG_MP_NUM_CPUS on SMP systems, you
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can see that using more cores takes almost linearly less time
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to complete the computational task.
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You can also edit the sample source code to change the
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number of digits calculated (``DIGITS_NUM``), and the
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number of threads to use (``THREADS_NUM``).
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Building and Running
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********************
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This project outputs Pi values calculated by each thread and in the end total time
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required for all the calculation to be done. It can be built and executed
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on Synopsys ARC HSDK board as follows:
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.. zephyr-app-commands::
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:zephyr-app: samples/smp_pi
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:host-os: unix
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:board: qemu_x86_64
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:goals: run
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:compact:
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Sample Output
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=============
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.. code-block:: console
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Calculate first 240 digits of Pi independently by 16 threads.
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Pi value calculated by thread #0: 3141592653589793238462643383279502884197...
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Pi value calculated by thread #1: 3141592653589793238462643383279502884197...
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...
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Pi value calculated by thread #14: 314159265358979323846264338327950288419...
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Pi value calculated by thread #15: 314159265358979323846264338327950288419...
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All 16 threads executed by 4 cores in 28 msec
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