X-Git-Url: http://git.droids-corp.org/?a=blobdiff_plain;f=doc%2Fguides%2Fprog_guide%2Fmempool_lib.rst;h=890535eb23483855383a97f81e6f2b9e04b41f43;hb=da97592635bbee01f72d76659d00720a62fa2d04;hp=1943fc4b2103d69cdc2a2b8cf965e61c484e38fe;hpb=449c49b93a6b87506c7bb07468e82b539efddca3;p=dpdk.git diff --git a/doc/guides/prog_guide/mempool_lib.rst b/doc/guides/prog_guide/mempool_lib.rst index 1943fc4b21..890535eb23 100644 --- a/doc/guides/prog_guide/mempool_lib.rst +++ b/doc/guides/prog_guide/mempool_lib.rst @@ -1,32 +1,5 @@ -.. BSD LICENSE - Copyright(c) 2010-2014 Intel Corporation. All rights reserved. - All rights reserved. - - Redistribution and use in source and binary forms, with or without - modification, are permitted provided that the following conditions - are met: - - * Redistributions of source code must retain the above copyright - notice, this list of conditions and the following disclaimer. - * Redistributions in binary form must reproduce the above copyright - notice, this list of conditions and the following disclaimer in - the documentation and/or other materials provided with the - distribution. - * Neither the name of Intel Corporation nor the names of its - contributors may be used to endorse or promote products derived - from this software without specific prior written permission. - - THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS - "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT - LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR - A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT - OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, - SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT - LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, - DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY - THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT - (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE - OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. +.. SPDX-License-Identifier: BSD-3-Clause + Copyright(c) 2010-2014 Intel Corporation. .. _Mempool_Library: @@ -44,20 +17,19 @@ This library is used by the :ref:`Mbuf Library `. Cookies ------- -In debug mode (CONFIG_RTE_LIBRTE_MEMPOOL_DEBUG is enabled), cookies are added at the beginning and end of allocated blocks. +In debug mode, cookies are added at the beginning and end of allocated blocks. The allocated objects then contain overwrite protection fields to help debugging buffer overflows. Stats ----- -In debug mode (CONFIG_RTE_LIBRTE_MEMPOOL_DEBUG is enabled), -statistics about get from/put in the pool are stored in the mempool structure. +In debug mode, statistics about get from/put in the pool are stored in the mempool structure. Statistics are per-lcore to avoid concurrent access to statistics counters. -Memory Alignment Constraints ----------------------------- +Memory Alignment Constraints on x86 architecture +------------------------------------------------ -Depending on hardware memory configuration, performance can be greatly improved by adding a specific padding between objects. +Depending on hardware memory configuration on X86 architecture, performance can be greatly improved by adding a specific padding between objects. The objective is to ensure that the beginning of each object starts on a different channel and rank in memory so that all channels are equally loaded. This is particularly true for packet buffers when doing L3 forwarding or flow classification. @@ -115,9 +87,9 @@ While this may mean a number of buffers may sit idle on some core's cache, the speed at which a core can access its own cache for a specific memory pool without locks provides performance gains. The cache is composed of a small, per-core table of pointers and its length (used as a stack). -This cache can be enabled or disabled at creation of the pool. +This internal cache can be enabled or disabled at creation of the pool. -The maximum size of the cache is static and is defined at compilation time (CONFIG_RTE_MEMPOOL_CACHE_MAX_SIZE). +The maximum size of the cache is static and is defined at compilation time (RTE_MEMPOOL_CACHE_MAX_SIZE). :numref:`figure_mempool` shows a cache in operation. @@ -127,6 +99,12 @@ The maximum size of the cache is static and is defined at compilation time (CONF A mempool in Memory with its Associated Ring +Alternatively to the internal default per-lcore local cache, an application can create and manage external caches through the ``rte_mempool_cache_create()``, ``rte_mempool_cache_free()`` and ``rte_mempool_cache_flush()`` calls. +These user-owned caches can be explicitly passed to ``rte_mempool_generic_put()`` and ``rte_mempool_generic_get()``. +The ``rte_mempool_default_cache()`` call returns the default internal cache if any. +In contrast to the default caches, user-owned caches can be used by unregistered non-EAL threads too. + +.. _Mempool_Handlers: Mempool Handlers ------------------------ @@ -137,7 +115,7 @@ management systems and software based memory allocators, to be used with DPDK. There are two aspects to a mempool handler. * Adding the code for your new mempool operations (ops). This is achieved by - adding a new mempool ops code, and using the ``REGISTER_MEMPOOL_OPS`` macro. + adding a new mempool ops code, and using the ``MEMPOOL_REGISTER_OPS`` macro. * Using the new API to call ``rte_mempool_create_empty()`` and ``rte_mempool_set_ops_byname()`` to create a new mempool and specifying which @@ -156,6 +134,14 @@ For applications that use ``rte_pktmbuf_create()``, there is a config setting (``RTE_MBUF_DEFAULT_MEMPOOL_OPS``) that allows the application to make use of an alternative mempool handler. + .. note:: + + When running a DPDK application with shared libraries, mempool handler + shared objects specified with the '-d' EAL command-line parameter are + dynamically loaded. When running a multi-process application with shared + libraries, the -d arguments for mempool handlers *must be specified in the + same order for all processes* to ensure correct operation. + Use Cases ---------