GPUs as an Opportunity for Offloading Garbage Collection

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Martin Maas, Philip Reames, Jeffrey Morlan, Krste Asanović, Anthony D. Joseph, John Kubiatowicz. GPUs as an Opportunity for Offloading Garbage Collection. International Symposium on Memory Management 2012, Beijing, China, June 2012


GPUs have become part of most commodity systems. Nonetheless, they are often underutilized when not executing graphics-intensive or special-purpose numerical computations, which are rare in consumer workloads. Emerging architectures, such as integrated CPU/GPU combinations, may create an opportunity to utilize these otherwise unused cycles for offloading traditional systems tasks. Garbage collection appears to be a particularly promising candidate for offloading, due to the popularity of managed languages on consumer devices.

We investigate the challenges for offloading garbage collection to a GPU, by examining the performance trade-offs for the mark phase of a mark & sweep garbage collector. We present a theoretical analysis and an algorithm that demonstrates the feasibility of this approach. We also discuss a number of algorithmic design trade-offs required to leverage the strengths and capabilities of the GPU hardware. Our algorithm has been integrated into the Jikes RVM and we present promising performance results.

Categories and Subject Descriptors

D.3.4 [Processors]: Memory management (garbage collection); I.3.1 [Hardware Architecture]: Parallel processing


parallel garbage collection, mark and sweep, SIMT, GPU, APU