55 lines
2.1 KiB
ReStructuredText
55 lines
2.1 KiB
ReStructuredText
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Design
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======
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Environment or Architecture-specific Sources
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--------------------------------------------
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In DPDK and DPDK applications, some code is specific to an architecture (i686, x86_64) or to an executive environment (bsdapp or linuxapp) and so on.
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As far as is possible, all such instances of architecture or env-specific code should be provided via standard APIs in the EAL.
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By convention, a file is common if it is not located in a directory indicating that it is specific.
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For instance, a file located in a subdir of "x86_64" directory is specific to this architecture.
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A file located in a subdir of "linuxapp" is specific to this execution environment.
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.. note::
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Code in DPDK libraries and applications should be generic.
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The correct location for architecture or executive environment specific code is in the EAL.
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When absolutely necessary, there are several ways to handle specific code:
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* Use a ``#ifdef`` with the CONFIG option in the C code.
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This can be done when the differences are small and they can be embedded in the same C file:
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.. code-block: console
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#ifdef RTE_ARCH_I686
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toto();
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#else
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titi();
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#endif
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* Use the CONFIG option in the Makefile. This is done when the differences are more significant.
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In this case, the code is split into two separate files that are architecture or environment specific. This should only apply inside the EAL library.
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.. note:
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As in the linux kernel, the "CONFIG_" prefix is not used in C code.
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This is only needed in Makefiles or shell scripts.
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Per Architecture Sources
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~~~~~~~~~~~~~~~~~~~~~~~~
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The following config options can be used:
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* CONFIG_RTE_ARCH is a string that contains the name of the architecture.
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* CONFIG_RTE_ARCH_I686, CONFIG_RTE_ARCH_X86_64, CONFIG_RTE_ARCH_X86_64_32 or CONFIG_RTE_ARCH_PPC_64 are defined only if we are building for those architectures.
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Per Execution Environment Sources
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~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
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The following config options can be used:
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* CONFIG_RTE_EXEC_ENV is a string that contains the name of the executive environment.
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* CONFIG_RTE_EXEC_ENV_BSDAPP or CONFIG_RTE_EXEC_ENV_LINUXAPP are defined only if we are building for this execution environment.
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