Introduction to spead2

spead2 is an implementation of the SPEAD protocol, with both Python and C++ bindings. The 2 in the name indicates that this is a new implementation of the protocol; the protocol remains essentially the same. Compared to the PySPEAD implementation, spead2:

  • is at least an order of magnitude faster when dealing with large heaps;
  • correctly implements several aspects of the protocol that were implemented incorrectly in PySPEAD (bug-compatibility is also available);
  • correctly implements many corner cases on which PySPEAD would simply fail;
  • cleanly supports several SPEAD flavours (e.g. 64-40 and 64-48) in one module, with the receiver adapting to the flavour used by the sender;
  • supports Python 3;
  • supports asynchronous operation, using trollius.


spead2 requires a modern C++ compiler supporting C++11 (currently only GCC 4.8 and Clang 3.4 have been tried) as well as Boost (including compiled libraries). The Python bindings have additional dependencies — see below. At the moment only GNU/Linux has been tested but other POSIX-like systems should work too (OS X is tested occasionally).

There is optional support for netmap and ibverbs for higher performance. If the libraries (including development headers) libraries are installed, they will automatically be detected and used.

If you are installing spead2 from a git checkout, it is first necessary to run ./ to prepare the configure script and related files. When building from a packaged download this is not required.

High-performance usage requires larger buffer sizes than Linux allows by default. The following commands will increase the permitted buffer sizes on Linux:

sysctl net.core.wmem_max=16777216
sysctl net.core.rmem_max=16777216

Note that these commands are not persistent across reboots, and the settings need to be stored in /etc/sysctl.conf or /etc/sysctl.d.

Installing spead2 for Python

The only Python dependencies are numpy and six, although support for asynchronous I/O also requires trollius. Running the test suite additionally requires nose, decorator and netifaces, and some tests depend on PySPEAD (they will be skipped if it is not installed). It is also necessary to have the development headers for Python, and Boost.Python.

To install (which will automatically pull in the mandatory dependencies), run:

./ install

Other standard methods for installing Python packages should work too.

Installing spead2 for C++

The C++ API uses the standard autoconf installation flow i.e.:

./configure [options]
make install

For generic help with configuration, see INSTALL in the top level of the source distribution. Optional features are autodetected by default, but can be disabled by passing options to configure (run ./configure -h to see a list of options).

The installation will install some benchmark tools, a static library, and the header files. At the moment there is no intention to create a shared library, because the ABI is not stable.