sys_reqs.rst revision 97f17497
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30
31System Requirements
32===================
33
34This chapter describes the packages required to compile the DPDK.
35
36.. note::
37
38    If the DPDK is being used on an Intel® Communications Chipset 89xx Series platform,
39    please consult the *Intel® Communications Chipset 89xx Series Software for Linux Getting Started Guide*.
40
41BIOS Setting Prerequisite on x86
42--------------------------------
43
44For the majority of platforms, no special BIOS settings are needed to use basic DPDK functionality.
45However, for additional HPET timer and power management functionality,
46and high performance of small packets on 40G NIC, BIOS setting changes may be needed.
47Consult the section on :ref:`Enabling Additional Functionality <Enabling_Additional_Functionality>`
48for more information on the required changes.
49
50Compilation of the DPDK
51-----------------------
52
53**Required Tools:**
54
55.. note::
56
57    Testing has been performed using Fedora 18. The setup commands and installed packages needed on other systems may be different.
58    For details on other Linux distributions and the versions tested, please consult the DPDK Release Notes.
59
60*   GNU ``make``.
61
62*   coreutils: ``cmp``, ``sed``, ``grep``, ``arch``, etc.
63
64*   gcc: versions 4.5.x or later is recommended for ``i686/x86_64``. Versions 4.8.x or later is recommended
65    for ``ppc_64`` and ``x86_x32`` ABI. On some distributions, some specific compiler flags and linker flags are enabled by
66    default and affect performance (``-fstack-protector``, for example). Please refer to the documentation
67    of your distribution and to ``gcc -dumpspecs``.
68
69*   libc headers, often packaged as ``gcc-multilib`` (``glibc-devel.i686`` / ``libc6-dev-i386``;
70    ``glibc-devel.x86_64`` / ``libc6-dev`` for 64-bit compilation on Intel architecture;
71    ``glibc-devel.ppc64`` for 64 bit IBM Power architecture;)
72
73*   Linux kernel headers or sources required to build kernel modules. (kernel - devel.x86_64;
74    kernel - devel.ppc64)
75
76*   Additional packages required for 32-bit compilation on 64-bit systems are:
77
78    * glibc.i686, libgcc.i686, libstdc++.i686 and glibc-devel.i686 for Intel i686/x86_64;
79
80    * glibc.ppc64, libgcc.ppc64, libstdc++.ppc64 and glibc-devel.ppc64 for IBM ppc_64;
81
82.. note::
83
84    x86_x32 ABI is currently supported with distribution packages only on Ubuntu
85    higher than 13.10 or recent Debian distribution. The only supported  compiler is gcc 4.8+.
86
87.. note::
88
89    Python, version 2.6 or 2.7, to use various helper scripts included in the DPDK package.
90
91
92**Optional Tools:**
93
94*   Intel® C++ Compiler (icc). For installation, additional libraries may be required.
95    See the icc Installation Guide found in the Documentation directory under the compiler installation.
96
97*   IBM® Advance ToolChain for Powerlinux. This is a set of open source development tools and runtime libraries
98    which allows users to take leading edge advantage of IBM's latest POWER hardware features on Linux. To install
99    it, see the IBM official installation document.
100
101*   libpcap headers and libraries (libpcap-devel) to compile and use the libpcap-based poll-mode driver.
102    This driver is disabled by default and can be enabled by setting ``CONFIG_RTE_LIBRTE_PMD_PCAP=y`` in the build time config file.
103
104Running DPDK Applications
105-------------------------
106
107To run an DPDK application, some customization may be required on the target machine.
108
109System Software
110~~~~~~~~~~~~~~~
111
112**Required:**
113
114*   Kernel version >= 2.6.34
115
116    The kernel version in use can be checked using the command::
117
118        uname -r
119
120*   glibc >= 2.7 (for features related to cpuset)
121
122    The version can be checked using the ``ldd --version`` command.
123
124*   Kernel configuration
125
126    In the Fedora OS and other common distributions, such as Ubuntu, or Red Hat Enterprise Linux,
127    the vendor supplied kernel configurations can be used to run most DPDK applications.
128
129    For other kernel builds, options which should be enabled for DPDK include:
130
131    *   UIO support
132
133    *   HUGETLBFS
134
135    *   PROC_PAGE_MONITOR  support
136
137    *   HPET and HPET_MMAP configuration options should also be enabled if HPET  support is required.
138        See the section on :ref:`High Precision Event Timer (HPET) Functionality <High_Precision_Event_Timer>` for more details.
139
140.. _linux_gsg_hugepages:
141
142Use of Hugepages in the Linux Environment
143~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
144
145Hugepage support is required for the large memory pool allocation used for packet buffers
146(the HUGETLBFS option must be enabled in the running kernel as indicated the previous section).
147By using hugepage allocations, performance is increased since fewer pages are needed,
148and therefore less Translation Lookaside Buffers (TLBs, high speed translation caches),
149which reduce the time it takes to translate a virtual page address to a physical page address.
150Without hugepages, high TLB miss rates would occur with the standard 4k page size, slowing performance.
151
152Reserving Hugepages for DPDK Use
153^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
154
155The allocation of hugepages should be done at boot time or as soon as possible after system boot
156to prevent memory from being fragmented in physical memory.
157To reserve hugepages at boot time, a parameter is passed to the Linux kernel on the kernel command line.
158
159For 2 MB pages, just pass the hugepages option to the kernel. For example, to reserve 1024 pages of 2 MB, use::
160
161    hugepages=1024
162
163For other hugepage sizes, for example 1G pages, the size must be specified explicitly and
164can also be optionally set as the default hugepage size for the system.
165For example, to reserve 4G of hugepage memory in the form of four 1G pages, the following options should be passed to the kernel::
166
167    default_hugepagesz=1G hugepagesz=1G hugepages=4
168
169.. note::
170
171    The hugepage sizes that a CPU supports can be determined from the CPU flags on Intel architecture.
172    If pse exists, 2M hugepages are supported; if pdpe1gb exists, 1G hugepages are supported.
173    On IBM Power architecture, the supported hugepage sizes are 16MB and 16GB.
174
175.. note::
176
177    For 64-bit applications, it is recommended to use 1 GB hugepages if the platform supports them.
178
179In the case of a dual-socket NUMA system,
180the number of hugepages reserved at boot time is generally divided equally between the two sockets
181(on the assumption that sufficient memory is present on both sockets).
182
183See the Documentation/kernel-parameters.txt file in your Linux source tree for further details of these and other kernel options.
184
185**Alternative:**
186
187For 2 MB pages, there is also the option of allocating hugepages after the system has booted.
188This is done by echoing the number of hugepages required to a nr_hugepages file in the ``/sys/devices/`` directory.
189For a single-node system, the command to use is as follows (assuming that 1024 pages are required)::
190
191    echo 1024 > /sys/kernel/mm/hugepages/hugepages-2048kB/nr_hugepages
192
193On a NUMA machine, pages should be allocated explicitly on separate nodes::
194
195    echo 1024 > /sys/devices/system/node/node0/hugepages/hugepages-2048kB/nr_hugepages
196    echo 1024 > /sys/devices/system/node/node1/hugepages/hugepages-2048kB/nr_hugepages
197
198.. note::
199
200    For 1G pages, it is not possible to reserve the hugepage memory after the system has booted.
201
202Using Hugepages with the DPDK
203^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
204
205Once the hugepage memory is reserved, to make the memory available for DPDK use, perform the following steps::
206
207    mkdir /mnt/huge
208    mount -t hugetlbfs nodev /mnt/huge
209
210The mount point can be made permanent across reboots, by adding the following line to the ``/etc/fstab`` file::
211
212    nodev /mnt/huge hugetlbfs defaults 0 0
213
214For 1GB pages, the page size must be specified as a mount option::
215
216    nodev /mnt/huge_1GB hugetlbfs pagesize=1GB 0 0
217
218Xen Domain0 Support in the Linux Environment
219~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
220
221The existing memory management implementation is based on the Linux kernel hugepage mechanism.
222On the Xen hypervisor, hugepage support for DomainU (DomU) Guests means that DPDK applications work as normal for guests.
223
224However, Domain0 (Dom0) does not support hugepages.
225To work around this limitation, a new kernel module rte_dom0_mm is added to facilitate the allocation and mapping of memory via
226**IOCTL** (allocation) and **MMAP** (mapping).
227
228Enabling Xen Dom0 Mode in the DPDK
229^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
230
231By default, Xen Dom0 mode is disabled in the DPDK build configuration files.
232To support Xen Dom0, the CONFIG_RTE_LIBRTE_XEN_DOM0 setting should be changed to “y”, which enables the Xen Dom0 mode at compile time.
233
234Furthermore, the CONFIG_RTE_EAL_ALLOW_INV_SOCKET_ID setting should also be changed to “y” in the case of the wrong socket ID being received.
235
236Loading the DPDK rte_dom0_mm Module
237^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
238
239To run any DPDK application on Xen Dom0, the ``rte_dom0_mm`` module must be loaded into the running kernel with rsv_memsize option.
240The module is found in the kmod sub-directory of the DPDK target directory.
241This module should be loaded using the insmod command as shown below (assuming that the current directory is the DPDK target directory)::
242
243    sudo insmod kmod/rte_dom0_mm.ko rsv_memsize=X
244
245The value X cannot be greater than 4096(MB).
246
247Configuring Memory for DPDK Use
248^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
249
250After the rte_dom0_mm.ko kernel module has been loaded, the user must configure the memory size for DPDK usage.
251This is done by echoing the memory size to a memsize file in the /sys/devices/ directory.
252Use the following command (assuming that 2048 MB is required)::
253
254    echo 2048 > /sys/kernel/mm/dom0-mm/memsize-mB/memsize
255
256The user can also check how much memory has already been used::
257
258    cat /sys/kernel/mm/dom0-mm/memsize-mB/memsize_rsvd
259
260Xen Domain0 does not support NUMA configuration, as a result the ``--socket-mem`` command line option is invalid for Xen Domain0.
261
262.. note::
263
264    The memsize value cannot be greater than the rsv_memsize value.
265
266Running the DPDK Application on Xen Domain0
267^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
268
269To run the DPDK application on Xen Domain0, an extra command line option ``--xen-dom0`` is required.
270