Nanos++ is a runtime library designed to serve as runtime support in parallel environments. It is mainly used to support OmpSs (an extension to the OpenMP programming model) developed at BSC, but it also has modules to support OpenMP and Chapel.
The runtime provides several services to support task parallelism using synchronizations based on data-dependencies. Data parallelism is also supported by means of services mapped on top of its task support. Task are implemented as user-level threads when possible (currently x86, x86-64, ia64, arm, ppc32 and ppc64 are supported). It also provides support for maintaining coherence across different address spaces (such as with GPUs or cluster nodes).
The main purpose of Nanos++ is to be used in research of parallel programming environments. Our aim has been to enable easy development of different parts of the runtime so researchers have a platform that allows them to try different mechanisms. As such it is designed to be extensible by means of plugins: the scheduling policy, the throttling policy, the dependence approach, the barrier implementations, the slicers implementation, the instrumentation layer and the architectural level. This extensibility does not come for free. The runtime overheads are slightly increased, but there should be low enough for results to be meaningful except for cases of extreme-fine grain applications.
Creating New Issues
Should you find a bug or want to make a feature request you can create a new ticket. As Nanos++ is a medium-sized piece of software so, in order to make bug tracking as useful as possible, you may want to read these guidelines:
Before reporting an issue spend some time checking existing ones. Maybe your problem has already been reported and a fix is ongoing or planned. Duplicated issues will be resolved as duplicated and no further action will be taken on them. Sometimes it is not obvious what is duplicated or not and you will have serious doubts about it. In this case just create the issue and add references to those issues you believe related with in its description.
Please, try to make a useful report. Where useful means we can figure out the source of your problem. A gdb backtrace it can be useful to use, be sure to use the debug version of Nanos++ in order to obtain an accurate backtrace. The debug version can be enabled passing the --debug flag to Mercurium when the application is built.
Use the CC field to stay tuned to changes in a bug. Add your username or e-mail there to track a bug and receive all the notifications due the different actions taken in this ticket.
If you have any questions or suggestions you can send an email to pm-tools*. You can also join the pm-tools-users mailing list by sending an e-mail to pm-tools-users-join*.
(*) All our email accounts are hosted at bsc.es (i.e. <account-name>@bsc.es).