79e6b0e0f6
As of today <zephyr/zephyr.h> is 100% equivalent to <zephyr/kernel.h>. This patch proposes to then include <zephyr/kernel.h> instead of <zephyr/zephyr.h> since it is more clear that you are including the Kernel APIs and (probably) nothing else. <zephyr/zephyr.h> sounds like a catch-all header that may be confusing. Most applications need to include a bunch of other things to compile, e.g. driver headers or subsystem headers like BT, logging, etc. The idea of a catch-all header in Zephyr is probably not feasible anyway. Reason is that Zephyr is not a library, like it could be for example `libpython`. Zephyr provides many utilities nowadays: a kernel, drivers, subsystems, etc and things will likely grow. A catch-all header would be massive, difficult to keep up-to-date. It is also likely that an application will only build a small subset. Note that subsystem-level headers may use a catch-all approach to make things easier, though. NOTE: This patch is **NOT** removing the header, just removing its usage in-tree. I'd advocate for its deprecation (add a #warning on it), but I understand many people will have concerns. Signed-off-by: Gerard Marull-Paretas <gerard.marull@nordicsemi.no> |
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| src | ||
| CMakeLists.txt | ||
| README.rst | ||
| prj.conf | ||
| sample.yaml | ||
README.rst
.. _smp_pi:
SMP Pi
###########
Overview
********
This sample application calculates Pi independently in many threads, and
demonstrates the benefit of multiple execution units (CPU cores)
when compute-intensive tasks can be run in parallel, with
no cross-dependencies or shared resources.
By changing the value of CONFIG_MP_NUM_CPUS on SMP systems, you
can see that using more cores takes almost linearly less time
to complete the computational task.
You can also edit the sample source code to change the
number of digits calculated (``DIGITS_NUM``), and the
number of threads to use (``THREADS_NUM``).
Building and Running
********************
This project outputs Pi values calculated by each thread and in the end total time
required for all the calculation to be done. It can be built and executed
on Synopsys ARC HSDK board as follows:
.. zephyr-app-commands::
:zephyr-app: samples/smp/pi
:host-os: unix
:board: qemu_x86_64
:goals: run
:compact:
Sample Output
=============
.. code-block:: console
Calculate first 240 digits of Pi independently by 16 threads.
Pi value calculated by thread #0: 3141592653589793238462643383279502884197...
Pi value calculated by thread #1: 3141592653589793238462643383279502884197...
...
Pi value calculated by thread #14: 314159265358979323846264338327950288419...
Pi value calculated by thread #15: 314159265358979323846264338327950288419...
All 16 threads executed by 4 cores in 28 msec