From: Eelco Chaudron Date: Mon, 2 Oct 2017 10:01:40 +0000 (+0200) Subject: doc: add use of mlockall to programmers guide X-Git-Tag: spdx-start~1675 X-Git-Url: http://git.droids-corp.org/?a=commitdiff_plain;h=7a8889324654c9e39f9e18097ccc74d6ff2588cf;p=dpdk.git doc: add use of mlockall to programmers guide When I was adding mlockall() to the testpmd application it was suggested to add a reference to the use case of mlockall(). This patch adds is. Signed-off-by: Eelco Chaudron Acked-by: John McNamara --- diff --git a/doc/guides/prog_guide/writing_efficient_code.rst b/doc/guides/prog_guide/writing_efficient_code.rst index 8223aceeab..d7ac6778bb 100644 --- a/doc/guides/prog_guide/writing_efficient_code.rst +++ b/doc/guides/prog_guide/writing_efficient_code.rst @@ -105,6 +105,21 @@ meaning that if all memory access operations are done on the first channel only, By default, the :ref:`Mempool Library ` spreads the addresses of objects among memory channels. +Locking memory pages +~~~~~~~~~~~~~~~~~~~~ + +The underlying operating system is allowed to load/unload memory pages at its own discretion. +These page loads could impact the performance, as the process is on hold when the kernel fetches them. + +To avoid these you could pre-load, and lock them into memory with the ``mlockall()`` call. + +.. code-block:: c + + if (mlockall(MCL_CURRENT | MCL_FUTURE)) { + RTE_LOG(NOTICE, USER1, "mlockall() failed with error \"%s\"\n", + strerror(errno)); + } + Communication Between lcores ----------------------------