Google Summer of Code 2016 wrap-up: STE||AR

Tuesday, November 29, 2016

This is part of a series of guest posts from students, mentors and organization administrators who participated in Google Summer of Code (GSoC) 2016. GSoC is an annual program which pairs university students with mentors to work on open source software.

This summer the STE||AR Group was proud to mentor four students through Google Summer of Code. These students worked on a variety of projects which helped improve our software, HPX. This library is a distributed C++ runtime system which supports a standards compliant API and helps users scale their applications across thousands of machines.

The improvements to the code base will help our team and users of HPX around the world. A summary of our students’ projects:

Parsa Amini – HPX Debugger

Developing a better distributed debugging tool is essential to increase the programmability of HPX. Parsa’s project, Scimitar, aims to facilitate the debugging process for HPX programmers by extending the features of GDB, an existing debugger. The project then complements it with new commands for easier switching between localities across clusters, HPX thread debugging, awareness of internal HPX data structures, and semi-automated preparation for distributed debugging sessions. Additional functionality such as locating an object and viewing the queue information on each core is provided through using API provided by HPX itself. His work can be found on GitHub.

Aalekh Nigam – Implement a Map/Reduce Framework

This project aimed to expose a Map/Reduce programming model over HPX. During the summer, Aalekh was able to develop a single node implementation of HPXflow (map/reduce programming model) and laid the groundwork for the further multi-node version with database support. Although the initial task was limited to implementing the Map/Reduce model, he was also able to implement an improved dataflow model as well.

Minh-Khanh Do - Working on Parallel Algorithms for HPX::Vector

Minh-Khanh’s task was to take the parallel algorithms and add the functionality required to work on the segmented hpx::vector. Under his mentor John Biddscombe, he implemented the segmented_fill algorithm, which was successfully merged into the main codebase. Additionally, Minh-Khanh implemented the segmented_scan algorithm which includes inclusive and exclusive_scan. These changes are included in a pull request and have been merged. Using the segmented scan algorithm it is possible to perform tasks such as evaluating polynomials and to implement other algorithms such as quicksort.

Satyaki Upadhyay - Plugin Mechanism for thread schedulers in HPX

In HPX, schedulers are statically linked and must be built at compile-time. Satyaki’s project involved converting this statically linked scheme into a plugin system which would allow arbitrary schedulers to be dynamically loaded. These changes bring several benefits. They provide a layer of abstraction and follow the open/closed principle of software design as well as allowing developers to write their own custom schedulers while conforming to a uniform API. The project proceeded in two steps. The first involved the creation of plugin modules of the schedulers and registering them with HPX. The second step was to implement the loading and subsequent use of the chosen scheduler.

We would like to thank our students and mentors for the time that they have contributed to HPX this summer. In addition, we would like to thank Google for the opportunity that they provided the STE||AR Group to work with developers around the globe as well as the ability for students to interact with vibrant open source projects worldwide.

By Adrian Serio, Organization Administrator for The STE||AR Group