From mboxrd@z Thu Jan 1 00:00:00 1970 From: Eelco Chaudron Subject: [PATCH v2] doc: add use of mlockall to programmers guide Date: Mon, 2 Oct 2017 12:01:40 +0200 Message-ID: Cc: dev@dpdk.org To: john.mcnamara@intel.com Return-path: Received: from mx1.redhat.com (mx1.redhat.com [209.132.183.28]) by dpdk.org (Postfix) with ESMTP id A8A671B1F4 for ; Mon, 2 Oct 2017 12:01:21 +0200 (CEST) List-Id: DPDK patches and discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dev-bounces@dpdk.org Sender: "dev" 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 --- doc/guides/prog_guide/writing_efficient_code.rst | 15 +++++++++++++++ 1 file changed, 15 insertions(+) diff --git a/doc/guides/prog_guide/writing_efficient_code.rst b/doc/guides/prog_guide/writing_efficient_code.rst index 8223aceea..d7ac6778b 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 ---------------------------- -- 2.13.6