  Asymmetric sharing is a dynamic sharing model, where a shared data is heavily
accessed by a (local) sharer, and rarely accessed by other (remote) sharers. On
GPUs, without special support, asymmetric sharing requires heavily loaded
synchronization on every access. With the introduction of Remote Scope
Promotion (RSP), access to the local sharer is allowed with lightweight
synchronization, while heavyweight synchronization is only used for remote
accesses where it is rarely needed. RSP ensures data consistency by promoting
local synchronizations on remote accesses. Unfortunately, the first
implementation of RSP is not a scalable solution. We offer a more efficient and
scalable RSP implementation. This new design, which we call sRSP, is based on
the monitoring of the local sharer and the selective execution of heavyweight
synchronization operations. We evaluated the sRSP with the time-detailed
Gem5-APU simulator and the results show that the sRSP improves performance by
an average of 29 percent on a 64 Compute Unit GPU.
