GASNet  is a network-independent and language-independent high-performance communication interface intended for use in implementing the runtime system for global address space languages, such as Unified Parallel C (UPC)  or Titanium . GASNet stands for "Global-Address Space Networking."
Goals of this research include:
Figure 1 shows the organization of the GASNet communication layer and its relation to the parallel language system.
The GASNet interface is divided into two distinct layers:
GASNet Core API
GASNet Extended API
GASNet has already been implemented on Myrinet/GM, Quadrics/elan, IBM/LAPI, and MPI (a fully portable implementation), and implementations are on the way for Infiniband, Gigabit Ethernet and other high-performance networks. This research effort includes carefully evaluating the performance characteristics for the target high-performance networks and interfaces , and developing strategies for best utilizing the network capabilities to implement low-latency, low-overhead, one-sided small put/gets and zero-copy high-bandwidth bulk transfers .
Figures 2 and 3 demonstrate the small-put/get "round-trip" latency and large-put/get bandwidth achieved by the Myrinet and Quadrics implementations of GASNet in various configurations and on several machines. The leftmost bar for each machine shows the performance of the fully portable GASNet-MPI implementation on that system (MPI-based core API, reference implementation of extended API). The middle bar for the Quadrics machines shows the performance of using the reference extended API with a natively-implemented GASNet-Quadrics core API. The rightmost bar for each machine shows the performance of a fully-native implementation of the GASNet core and extended API on the underlying network. We find this performance to be very competitive with the best performance achievable on these networks, therefore justifying the claim that GASNet is indeed a very lightweight, high-performance interface.
Figures 4 and 5 show the small-put/get "round-trip" latency for the fully-native GASNet-Quadrics and GASNet-Myrinet implementations over varying message sizes.
This work is done in conjunction with the Berkeley UPC compiler group, a joint effort between Lawrence Berkeley National Laboratory and UC Berkeley. GASNet is already being used as a communication system for the Berkeley UPC compiler and the UC Berkeley Titanium compiler, and several other global address space language research efforts are considering adopting GASNet.
Figure 1: High-level system organization for a GAS language using GASNet
Figure 2: Small put/get "round-trip" latency performance of GASNet-Myrinet and GASNet-Quadrics in several configurations and machines
Figure 3: Large put/get bandwidth performance of GASNet-Myrinet and GASNet-Quadrics in several configurations and machines
Figure 4: Put/get "round-trip" latency performance of GASNet-Quadrics over varying message size
Figure 5: Put/get "round-trip" latency performance of GASNet-Myrinet over varying message size