The command "meson build" causes a deprecation warning with meson 0.64.0.
WARNING: Running the setup command as `meson [options]` instead of
`meson setup [options]` is ambiguous and deprecated.
Therefore fix the examples in the documentation.
Cc: stable@dpdk.org
Signed-off-by: Stephen Hemminger <stephen@networkplumber.org>
Acked-by: Bruce Richardson <bruce.richardson@intel.com>
Acked-by: Zhangfei Gao <zhangfei.gao@linaro.org>
Signed-off-by: David Marchand <david.marchand@redhat.com>
Acked-by: Stanislaw Kardach <kda@semihalf.com>
Update Linux core isolation guide to include isolation from
timers, RCU processing and IRQs.
Signed-off-by: Pavan Nikhilesh <pbhagavatula@marvell.com>
Acked-by: Jerin Jacob <jerinj@marvell.com>
The 4.4 kernel was end of life in February 2022,
and the next LTS is 4.9 and it is reaching EOL in January 2023.
The main distro using 4.9 is Debian Stretch and it is no longer
supported. When DPDK 22.11 is released, the 4.9 kernel would
only be receiving fixes for three months; therefore
lets make the official version 4.14.
As always, current major enterprise Linux releases will continue
to be supported, but those releases don't track regular kernel
version numbering.
For full details on kernel support see:
https://www.kernel.org/category/releases.htmlhttps://en.wikipedia.org/wiki/Linux_kernel_version_history
Debian Stretch:
https://www.debian.org/releases/stretch/
Signed-off-by: Stephen Hemminger <stephen@networkplumber.org>
dpdk-pmdinfo.py does not produce any parseable output. The -r/--raw flag
merely prints multiple independent JSON lines which cannot be fed
directly to any JSON parser. Moreover, the script complexity is rather
high for such a simple task: extracting PMD_INFO_STRING from .rodata ELF
sections. Rewrite it so that it can produce valid JSON.
Remove the PCI database parsing for PCI-ID to Vendor-Device names
conversion. This should be done by external scripts (if really needed).
The script passes flake8, black, isort and pylint checks.
I have tested this with a matrix of python/pyelftools versions:
pyelftools
0.22 0.23 0.24 0.25 0.26 0.27 0.28 0.29
3.6 ok ok ok ok ok ok ok ok
3.7 ok ok ok ok ok ok ok ok
Python 3.8 ok ok ok ok ok ok ok ok
3.9 ok ok ok ok ok *ok ok ok
3.10 fail fail fail fail ok ok ok ok
* Also tested on FreeBSD
All failures with python 3.10 are related to the same issue:
File "elftools/construct/lib/container.py", line 5, in <module>
from collections import MutableMapping
ImportError: cannot import name 'MutableMapping' from 'collections'
Python 3.10 support is only available since pyelftools 0.26. The script
will only work with Python 3.6 and later.
Update the minimal system requirements, docs and release notes.
Signed-off-by: Robin Jarry <rjarry@redhat.com>
Tested-by: Ferruh Yigit <ferruh.yigit@amd.com>
Tested-by: Olivier Matz <olivier.matz@6wind.com>
Acked-by: Bruce Richardson <bruce.richardson@intel.com>
This patchset bumps the minimum meson version from 0.49.2 to 0.53.2.
Ideally, the minimum version should be 0.53 without a point release, but
some DPDK builds (mingw) are broken with 0.53.0 due to issue[1], fixed
by commit[2] in 0.53.1. Therefore we use the latest point release from
0.53 branch i.e. 0.53.2.
Some new features of interest which can now be used in DPDK with this
new minimum meson version:
* can do header-file checks directly inside find_library calls, rather
than needing a separate check.[v0.50].
* can pass multiple cross-files at the same time when cross-compiling
[v0.51].
* "alias_target" function, to allow use to give better/shorter names
for particular build objects [v0.52].
* auto-generation of clang-format [v0.50] and clang-tidy[v0.52] targets
when those tools are present and config dotfiles are present.
Similarly ctags and cscope are added as targets when those tools are
present [v0.53]
* meson module for filesystem operations, so meson can now check for the
presence of particular files or directories [v0.53].
* "summary" function to provide a configuration summary at the end of
the meson run [v0.53].
Plus many other features. See [3] for full details of each version.
[1] https://github.com/mesonbuild/meson/issues/6442
[2] https://github.com/mesonbuild/meson/pull/6457/commits/8e7a7c36b579
[3] https://mesonbuild.com/Release-notes.html
Signed-off-by: Bruce Richardson <bruce.richardson@intel.com>
Acked-by: David Marchand <david.marchand@redhat.com>
Add all necessary elements for DPDK to compile and run EAL on
LoongArch64 Soc.
This includes:
- EAL library implementation for LoongArch ISA.
- meson build structure for 'loongarch' architecture.
RTE_ARCH_LOONGARCH define is added for architecture identification.
- xmm_t structure operation stubs as there is no vector support in
the current version for LoongArch.
Compilation was tested on Debian and CentOS using loongarch64
cross-compile toolchain from x86 build hosts. Functions were tested
on Loongnix and Kylin which are two Linux distributions supported
LoongArch host based on Linux 4.19 maintained by Loongson
Corporation.
We also tested DPDK on LoongArch with some external applications,
including: Pktgen-DPDK, OVS, VPP.
The platform is currently marked as linux-only because there is no
other OS than Linux support LoongArch host currently.
The i40e PMD driver is disabled on LoongArch because of the absence
of vector support in the current version.
Similar to RISC-V, the compilation of following modules has been
disabled by this commit and will be re-enabled in later commits as
fixes are introduced:
net/ixgbe, net/memif, net/tap, example/l3fwd.
Signed-off-by: Min Zhou <zhoumin@loongson.cn>
NVIDIA acquired Mellanox Technologies in 2020.
The DPDK documentation and code might still include instances
of or references to Mellanox trademarks (like BlueField and ConnectX)
that are now NVIDIA trademarks.
The PCI IDs and copyrights are unchanged.
Signed-off-by: Thomas Monjalon <thomas@monjalon.net>
Acked-by: Gal Cohen <galco@nvidia.com>
The guide to run DPDK applications as non-root in Linux
did not provide specific instructions to configure the required access
and did not explain why each bit is needed.
The latter is important because running as non-root
is one of the ways to tighten security and grant minimal permissions.
Cc: stable@dpdk.org
Signed-off-by: Dmitry Kozlyuk <dkozlyuk@nvidia.com>
Acked-by: Bruce Richardson <bruce.richardson@intel.com>
Both the Linux and FreeBSD GSG docs had a "Documentation Roadmap"
section as part of the introduction page, and this contained the same
information, with only the reference to the GSGs themselves being
different. This text can be consolidated into a single text file which
is included by both GSG intro sections - using relative links for the
self reference.
Signed-off-by: Bruce Richardson <bruce.richardson@intel.com>
Acked-by: John McNamara <john.mcnamara@intel.com>
Add support for using hugepages for worker lcore stack memory. The
intent is to improve performance by reducing stack memory related TLB
misses and also by using memory local to the NUMA node of each lcore.
EAL option '--huge-worker-stack[=stack-size-in-kbytes]' is added to allow
the feature to be enabled at runtime. If the size is not specified,
the system pthread stack size will be used.
Signed-off-by: Don Wallwork <donw@xsightlabs.com>
Acked-by: Morten Brørup <mb@smartsharesystems.com>
Acked-by: Chengwen Feng <fengchengwen@huawei.com>
Add all necessary elements for DPDK to compile and run EAL on SiFive
Freedom U740 SoC which is based on SiFive U74-MC (ISA: rv64imafdc)
core complex.
This includes:
- EAL library implementation for rv64imafdc ISA.
- meson build structure for 'riscv' architecture. RTE_ARCH_RISCV define
is added for architecture identification.
- xmm_t structure operation stubs as there is no vector support in the
U74 core.
Compilation was tested on Ubuntu and Arch Linux using riscv64 toolchain.
Clang compilation currently not supported due to issues with missing
relocation relaxation.
Two rte_rdtsc() schemes are provided: stable low-resolution using rdtime
(default) and unstable high-resolution using rdcycle. User can override
the scheme by defining RTE_RISCV_RDTSC_USE_HPM=1 during compile time of
both DPDK and the application. The reasoning for this is as follows.
The RISC-V ISA mandates that clock read by rdtime has to be of constant
period and synchronized between all hardware threads within 1 tick
(chapter 10.1 in version 20191213 of RISC-V spec).
However this clock may not be of high-enough frequency for dataplane
uses. I.e. on HiFive Unmatched (FU740) it is 1MHz.
There is a high-resolution alternative in form of rdcycle which is
clocked at the core clock frequency. The drawbacks are that it may be
disabled during sleep (WFI), its frequency might change due to DVFS and
it is core-local and therefore cannot be used as a wall-clock. It can
however be used for micro-benchmarking user applications, similarly to
Aarch64's PMCCNTR PMU counter.
The platform is currently marked as linux-only because rte_cycles
implementation uses the timebase-frequency device-tree node read through
the proc file system. Such approach was chosen because Linux kernel
depends on the presence of this device-tree node.
The i40e PMD driver is disabled on RISC-V as the rv64gc ISA has no vector
operations.
The compilation of following modules has been disabled by this commit
and will be re-enabled in later commits as fixes are introduced:
net/ixgbe, net/memif, net/tap, example/l3fwd.
Sponsored-by: Frank Zhao <frank.zhao@starfivetech.com>
Sponsored-by: Sam Grove <sam.grove@sifive.com>
Signed-off-by: Michal Mazurek <maz@semihalf.com>
Signed-off-by: Stanislaw Kardach <kda@semihalf.com>
The docs mention modifications and additions to the cross file,
but there is no demonstration of how those should look like.
Signed-off-by: Juraj Linkeš <juraj.linkes@pantheon.tech>
Acked-by: Ruifeng Wang <ruifeng.wang@arm.com>
Numactl cross compilation doesn't work with clang, remove it
and fix the GCC cross compiler executable name.
Signed-off-by: Juraj Linkeš <juraj.linkes@pantheon.tech>
Acked-by: Ruifeng Wang <ruifeng.wang@arm.com>
The newer versions have an extra -none- in the name.
Signed-off-by: Juraj Linkeš <juraj.linkes@pantheon.tech>
Acked-by: Ruifeng Wang <ruifeng.wang@arm.com>
Remove CFLAGS and LDFLAGS since Meson doesn't support them well enough.
Add Meson alternatives: -Dc_args and -Dc_link_args on the command line
and in cross files.
Signed-off-by: Juraj Linkeš <juraj.linkes@pantheon.tech>
Acked-by: Ruifeng Wang <ruifeng.wang@arm.com>
The document roadmap section was missing any mention of the individual
drivers guides which are important for users. Add them to list.
Signed-off-by: Bruce Richardson <bruce.richardson@intel.com>
The document roadmap section called out the titles of other documents,
but these are better as hyperlinks.
Signed-off-by: Bruce Richardson <bruce.richardson@intel.com>
There are two warnings in the VFIO section about limitations of VFIO and
limitations on who can bind/unbind devices. Since these don't actually
describe any unsafe conditions, and are more informational, we can
change these to notes. This also helps emphasise the other warnings in
the documents which flag genuine security concerns.
Signed-off-by: Bruce Richardson <bruce.richardson@intel.com>
Rather than having separate sections for VFIO and VFIO no-iommu mode, as
well as a separate section further down the document on troubleshooting
VFIO, we can consolidate all these as subsections into a primary VFIO
section. This section starts with the basics of VFIO use, then covers
no-iommu mode, before moving on to the more advanced topics such as
creating VFs and ending with the troubleshooting subsection.
Signed-off-by: Bruce Richardson <bruce.richardson@intel.com>
To further de-emphasise UIO over the alternatives, we can move the UIO
section of the drivers page to the end of the document, giving more
prominence to VFIO and bifurcated drivers.
Signed-off-by: Bruce Richardson <bruce.richardson@intel.com>
The VFIO section of the page about Linux drivers was rather long and
unstructured. This can be improved by splitting it up into subsections,
to cover the specifics of memory limits and creating VFs. When moving
the various text notes into the relevant subsections, we can drop the
note about kernels earlier than 3.6, since DPDK no longer supports
kernels that old.
Signed-off-by: Bruce Richardson <bruce.richardson@intel.com>
VFIO is to be strongly preferred over UIO-based modules, so update our
text and examples to only refer to VFIO, giving an initial reference at
the start to UIO as a fallback option.
Signed-off-by: Bruce Richardson <bruce.richardson@intel.com>
While the details of VFIO and UIO may be of interest to some, most users
of the doc are likely primarily interested in how to bind their devices
to the kernel driver and then move on to running the app. Therefore, the
most important part of the "Linux Drivers" section of the GSG is the
subsection on "Binding and Unbinding", so put that first.
Signed-off-by: Bruce Richardson <bruce.richardson@intel.com>
The GSG has a note warning that use of UIO is inherently unsafe due to
lack of IOMMU protection. However, this was only flagged as a "NOTE",
meaning it could easily be missed. Changing the rst tag from "note" to
"warning" and moving it to the top of the UIO subsection makes this a
lot more visible to users.
Signed-off-by: Bruce Richardson <bruce.richardson@intel.com>
The docs on binding drivers was updated as part of the removal of the
igb_uio module from the main DPDK repo. As part of that update, a note
about uio_pci_generic requiring legacy interrupts was removed, but
should have been kept.
Fixes: 56bb5841fd ("kernel/linux: remove igb_uio")
Cc: stable@dpdk.org
Signed-off-by: Bruce Richardson <bruce.richardson@intel.com>
Some IDEs, such as eclipse, complained on save about the use of special
characters in the (R) symbol in linux GSG doc. We can replace those with
the equivalent "|reg|" text, and including isonum.txt.
Cc: stable@dpdk.org
Signed-off-by: Bruce Richardson <bruce.richardson@intel.com>
The "Linux Drivers" section of the GSG already notes that, for use of
UIO, the IOMMU must be disabled or put into pass-through mode.
Therefore, there is no need to duplicate this information in the
"additional functionality" section. Also the kernel configuration
options documented in the section are enabled as standard on all common
distro kernels, so the information should not be needed in a GSG doc.
Signed-off-by: Bruce Richardson <bruce.richardson@intel.com>
The KNI library is disabled by default in DPDK and is already documented
in the programmers guide and also in the sample application guide. There
are also in-kernel alternatives to it. Therefore, we can drop the
(already fairly minimal) reference to it from the Linux GSG.
Signed-off-by: Bruce Richardson <bruce.richardson@intel.com>
As best we can tell, the HPET timers are not commonly used, so there is
little need to give extensive detail and commentry on them in the Linux
GSG. As such, we can reduce the GSG section to just a single subsection
and also move it down the page below items which are likely of greater
importance.
Signed-off-by: Bruce Richardson <bruce.richardson@intel.com>
Not all directories were given in the GSG document, but many of those
omitted would be of interest to users, e.g. "doc", "license" and
"usertools" directories. Adding these leaves only "devtools", and
"kernel" as the only undocumented directories, so add them in too for
completeness.
When updating the section, add "including" to the line leading up to the
directory list, indicating that, while the list is currently complete,
it is not guaranteed to always be.
Signed-off-by: Bruce Richardson <bruce.richardson@intel.com>
When building end-applications linked with DPDK, the only additional
tool needed is pkg-config/pkgconf. However, the standard development
tools meta-packages on most distro's include this as standard, meaning
it does not really require its own section. The one outlier in the
existing text is "alpine" where it is not present when using "libc-dev"
target. However, changing "gcc" and "libc-dev" to "alpine-sdk"
metapackage aligns alpine with the other distros in this regard.
Signed-off-by: Bruce Richardson <bruce.richardson@intel.com>
A note about secure boot not allowing UIO is present in both the system
requirements section and the driver binding section. This fits better in
the driver binding section, so the copy in system requirements can be
removed. The document in general now also emphasises VFIO over UIO more
than when this note was first added, reducing the need for this warning
to be repeated.
Signed-off-by: Bruce Richardson <bruce.richardson@intel.com>
Expose Linux EAL ability to reuse existing hugepage files
via --huge-unlink=never switch.
Default behavior is unchanged, it can also be specified
using --huge-unlink=existing for consistency.
Old --huge-unlink switch is kept,
it is an alias for --huge-unlink=always.
Add a test case for the --huge-unlink=never mode.
Signed-off-by: Dmitry Kozlyuk <dkozlyuk@nvidia.com>
Acked-by: Thomas Monjalon <thomas@monjalon.net>
Acked-by: Anatoly Burakov <anatoly.burakov@intel.com>
Removing the use of driver following PMD as its unnecessary.
Cc: stable@dpdk.org
Signed-off-by: Sean Morrissey <sean.morrissey@intel.com>
Signed-off-by: Conor Fogarty <conor.fogarty@intel.com>
Acked-by: John McNamara <john.mcnamara@intel.com>
Reviewed-by: Conor Walsh <conor.walsh@intel.com>
Reviewed-by: Ferruh Yigit <ferruh.yigit@intel.com>
Currently, the documentation only contains instructions for enabling
SRIOV support for VFIO compiled as a module, but doesn't have any
instructions on how to do the same for cases where VFIO is built-in.
Add these instructions.
Signed-off-by: Anatoly Burakov <anatoly.burakov@intel.com>
Acked-by: Bruce Richardson <bruce.richardson@intel.com>
Acked-by: Bernard Iremonger <bernard.iremonger@intel.com>
This option should be prefixed with -- for consistency with others.
Fixes: a103a97e71 ("eal: allow user to override default mempool driver")
Cc: stable@dpdk.org
Signed-off-by: David Marchand <david.marchand@redhat.com>
Reviewed-by: Olivier Matz <olivier.matz@6wind.com>
get_hugepage_dir() was implemented in such a way that a --huge-dir
option had to exactly match the mountpoint, but there's no reason for
this restriction: DPDK might not be the only user of hugepages, and
shouldn't assume it owns an entire mountpoint. For example, if I have
/dev/hugepages/myapp, and /dev/hugepages/dpdk, I should be able to
specify:
--huge-dir=/dev/hugepages/dpdk/
and have DPDK only use that sub-directory.
Fix the implementation to allow a sub-directory within a suitable
hugetlbfs mountpoint to be specified, preferring the closest match.
Signed-off-by: John Levon <john.levon@nutanix.com>
Acked-by: Dmitry Kozlyuk <dmitry.kozliuk@gmail.com>
Reviewed-by: David Marchand <david.marchand@redhat.com>
Add cross-compiling guidance for 32-bit aarch32 DPDK on aarch64 host.
Signed-off-by: Phil Yang <phil.yang@arm.com>
Acked-by: Ruifeng Wang <ruifeng.wang@arm.com>
Acked-by: Aaron Conole <aconole@redhat.com>
The current meson option 'machine' should only specify the ISA, which is
not sufficient for Arm, where setting ISA implies other settings as well
(and is used in Arm configuration as such).
Use the existing 'platform' meson option to differentiate the type of
the build (native/generic) and set ISA accordingly, unless the user
chooses to override it with a new option, 'cpu_instruction_set'.
The 'machine' option set the ISA in x86 builds and set native/default
'build type' in aarch64 builds. These two new variables, 'platform' and
'cpu_instruction_set', now properly set both ISA and build type for all
architectures in a uniform manner.
The 'machine' option also doesn't describe very well what it sets. The
new option, 'cpu_instruction_set', is much more descriptive. Keep
'machine' for backwards compatibility.
Signed-off-by: Juraj Linkeš <juraj.linkes@pantheon.tech>
Acked-by: Bruce Richardson <bruce.richardson@intel.com>
The tool lstopo from hwloc package can provide a graphical
or textual view.
In its textual form, the option --merge gives a shorter summary
which fits well with the DPDK need.
Signed-off-by: Thomas Monjalon <thomas@monjalon.net>
The DPDK project is only committed to supporting upstream kernel
versions that are still in support. The 3.16 kernel has reached
End Of Life (in June 2020). The next LTS kernel is 4.4 and is
supported until February 2020.
This does not change the existing policy that distribution kernels
that are older are still supported.
Signed-off-by: Stephen Hemminger <stephen@networkplumber.org>
Acked-by: Thomas Monjalon <thomas@monjalon.net>
Keep the list of SoCs in a single place and include it so that the
documentation won't get outdated.
Fixes: 8f5ea6a464 ("config/arm: fix implementer and its SoCs")
Fixes: 1b4c86a721 ("config/arm: add Marvell CN10K")
Fixes: 7cf32a22b2 ("config/arm: add Hisilicon kunpeng")
Signed-off-by: David Marchand <david.marchand@redhat.com>
Reviewed-by: Jerin Jacob <jerinj@marvell.com>
Reviewed-by: Ruifeng Wang <ruifeng.wang@arm.com>
After many patches in several releases to make DPDK buildable with musl,
and few adjustments for busybox, it is time to show the support of DPDK
built in Alpine Linux.
Signed-off-by: Thomas Monjalon <thomas@monjalon.net>
Bump Meson required version to 0.49.2 which is chosen so as
to be provided by both redhat-8 and debian-10.
Update documentation and travis setup script accordingly.
This fixes the following warning:
WARNING: Project targeting '>= 0.47.1' but tried to use feature introduced
in '0.48.0': console arg in custom_target
'console' argument is used within kernel/linux/kni/meson.build
Signed-off-by: Gabriel Ganne <gabriel.ganne@6wind.com>
Acked-by: Bruce Richardson <bruce.richardson@intel.com>
Acked-by: Andrew Rybchenko <andrew.rybchenko@oktetlabs.ru>
Add Arm SoC configuration sets to Arm meson.build and add an arch
agnostic meson option, 'platform', to select from these SoC
configurations for meson native builds. This is preferable to
specifying a cross file when doing aarch64 -> aarch64 builds, since the
cross file specifies the toolchain as well.
Signed-off-by: Juraj Linkeš <juraj.linkes@pantheon.tech>
Reviewed-by: Honnappa Nagarahalli <honnappa.nagarahalli@arm.com>
Reviewed-by: Ruifeng Wang <ruifeng.wang@arm.com>
Tested-by: Pavan Nikhilesh <pbhagavatula@marvell.com>
Add support for enabling or disabling drivers for Arm cross build. Do
not implement any enable/disable lists yet.
Enabling drivers is useful when building for an SoC where we only want
to build a few drivers. That way the list won't be too long.
Similarly, disabling drivers is useful when we want to disable only a
few drivers.
Both of these are advantageous mainly in aarch64 -> aarch64 (or arch ->
same arch) builds, where the build machine may have the required driver
dependencies, yet we don't want to build drivers for a specific SoC.
If enable_drivers is a non-empty list, build only those drivers,
otherwise build all drivers and add them to enable_drivers. If
disable_drivers is non-empty list, build all drivers specified in
enable_drivers except those in disable_drivers.
There are two drivers, bus/pci and bus/vdev, which break the build if
not enabled. Address this by always enabling these if the user disables
them or doesn't specify in their allowlist.
Also remove the old Makefile arm configuration options which don't do
anything in Meson.
Signed-off-by: Juraj Linkeš <juraj.linkes@pantheon.tech>
Reviewed-by: Honnappa Nagarahalli <honnappa.nagarahalli@arm.com>
Reviewed-by: Ruifeng Wang <ruifeng.wang@arm.com>
Acked-by: Bruce Richardson <bruce.richardson@intel.com>
In order to save DMA entries limited by kernel both for external
memory and hugepage memory, an attempt was made to map physically
contiguous memory in one go. This cannot be done as VFIO IOMMU type1
does not support partially unmapping a previously mapped memory
region while Heap can request for multi page mapping and
partial unmapping.
Hence for going back to old method of mapping/unmapping at
memseg granularity, this commit reverts
commit d1c7c0cdf7 ("vfio: map contiguous areas in one go")
Also add documentation on what module parameter needs to be used
to increase the per-container dma map limit for VFIO.
Fixes: d1c7c0cdf7 ("vfio: map contiguous areas in one go")
Cc: stable@dpdk.org
Signed-off-by: Nithin Dabilpuram <ndabilpuram@marvell.com>
Acked-by: Anatoly Burakov <anatoly.burakov@intel.com>
Acked-by: David Christensen <drc@linux.vnet.ibm.com>
python-pyelftools is not packaged for RHEL/CentOS with
the exception of RHEL7 EPEL.
Add command to install it with pip.
Fixes: f0f93a7adf ("buildtools: use Python pmdinfogen")
Signed-off-by: Kevin Traynor <ktraynor@redhat.com>
Acked-by: Bruce Richardson <bruce.richardson@intel.com>
The tool dpdk-hugepages.py, added in DPDK 20.11,
is referenced in the guides instead of more complicate commands.
The original Linux commands are kept in linux_gsg/sys_reqs.rst
and nics/build_and_test.rst.
Suggested-by: Stephen Hemminger <stephen@networkplumber.org>
Signed-off-by: Thomas Monjalon <thomas@monjalon.net>
Acked-by: Stephen Hemminger <stephen@networkplumber.org>
