c518bd63c3
The old code modified the node next array prior to obtaining the thread
barrier. Then it updated the runtime node data, and upon barrier release
caused reforking of each worker thread. The reforking clones the main
thread nodes and reconstructs the runtime node structure. This cloning
is not 100% "deep" in the sense that the node next array is
shared (i.e., only the pointer is copied). So prior to the barrier being
obtained the node's next array is being changed while workers are
actively using it (bad). Treating the node next array as read-only in
the workers and sharing it is a decent optimization so instead of trying
to fix that just move the barrier a little earlier in the process to
protect the node next array as well.
This was tripping an assert in next frame ownership change by way of the
ip4-arp node. The assert verifies that the node's next array length is
equal to the runtime next node count. The race above was lost and the
node next array data was updated in the main thread while the arp code
was still executing in a worker.
This was being hit when many arp requests were being sent from both ends
of a tunnel during which the add next node function was called, which
often led to an assert b/c the next node array was out of sync with the
runtime next node count.
- PS#2 update - move barrier sync to just above code that modifies state.
Ticket: VPP-1783
Type: fix
Signed-off-by: Christian E. Hopps <chopps@chopps.org>
Change-Id: I868784e28f994ee0922aaaae11c4894a3f4f1fe7
Signed-off-by: Christian E. Hopps <chopps@chopps.org>
(cherry picked from commit d3122ef4ec)
Vector Packet Processing
Introduction
The VPP platform is an extensible framework that provides out-of-the-box production quality switch/router functionality. It is the open source version of Cisco's Vector Packet Processing (VPP) technology: a high performance, packet-processing stack that can run on commodity CPUs.
The benefits of this implementation of VPP are its high performance, proven technology, its modularity and flexibility, and rich feature set.
For more information on VPP and its features please visit the FD.io website and What is VPP? pages.
Changes
Details of the changes leading up to this version of VPP can be found under @ref release_notes.
Directory layout
| Directory name | Description |
|---|---|
| build-data | Build metadata |
| build-root | Build output directory |
| doxygen | Documentation generator configuration |
| dpdk | DPDK patches and build infrastructure |
| @ref extras/libmemif | Client library for memif |
| @ref src/examples | VPP example code |
| @ref src/plugins | VPP bundled plugins directory |
| @ref src/svm | Shared virtual memory allocation library |
| src/tests | Standalone tests (not part of test harness) |
| src/vat | VPP API test program |
| @ref src/vlib | VPP application library |
| @ref src/vlibapi | VPP API library |
| @ref src/vlibmemory | VPP Memory management |
| @ref src/vnet | VPP networking |
| @ref src/vpp | VPP application |
| @ref src/vpp-api | VPP application API bindings |
| @ref src/vppinfra | VPP core library |
| @ref src/vpp/api | Not-yet-relocated API bindings |
| test | Unit tests and Python test harness |
Getting started
In general anyone interested in building, developing or running VPP should consult the VPP wiki for more complete documentation.
In particular, readers are recommended to take a look at [Pulling, Building, Running, Hacking, Pushing](https://wiki.fd.io/view/VPP/Pulling,_Building,_Run ning,_Hacking_and_Pushing_VPP_Code) which provides extensive step-by-step coverage of the topic.
For the impatient, some salient information is distilled below.
Quick-start: On an existing Linux host
To install system dependencies, build VPP and then install it, simply run the
build script. This should be performed a non-privileged user with sudo
access from the project base directory:
./extras/vagrant/build.sh
If you want a more fine-grained approach because you intend to do some
development work, the Makefile in the root directory of the source tree
provides several convenience shortcuts as make targets that may be of
interest. To see the available targets run:
make
Quick-start: Vagrant
The directory extras/vagrant contains a VagrantFile and supporting
scripts to bootstrap a working VPP inside a Vagrant-managed Virtual Machine.
This VM can then be used to test concepts with VPP or as a development
platform to extend VPP. Some obvious caveats apply when using a VM for VPP
since its performance will never match that of bare metal; if your work is
timing or performance sensitive, consider using bare metal in addition or
instead of the VM.
For this to work you will need a working installation of Vagrant. Instructions for this can be found [on the Setting up Vagrant wiki page] (https://wiki.fd.io/view/DEV/Setting_Up_Vagrant).
More information
Several modules provide documentation, see @subpage user_doc for more end-user-oriented information. Also see @subpage dev_doc for developer notes.
Visit the VPP wiki for details on more advanced building strategies and other development notes.
Test Framework
There is PyDoc generated documentation available for the VPP test framework. See @ref test_framework_doc for details.