Search for: All records

We present RAINBLOCK, a public blockchain that achieves high transaction throughput without modifying the proof-ofwork consensus. The chief insight behind RAINBLOCK is that while consensus controls the rate at which new blocks are added to the blockchain, the number of transactions in each block is limited by I/O bottlenecks. Public blockchains like Ethereum keep the number of transactions in each block low so that all participating servers (miners) have enough time to process a block before the next block is created. By removing the I/O bottlenecks in transaction processing, RAINBLOCK allows miners to process more transactions in the same amount of time. RAINBLOCK makes two novel contributions: the RAINBLOCK architecture that removes I/O from the critical path of processing transactions (txs), and the distributed, multiversioned DSM-TREE data structure that stores the system state efficiently. We evaluate RAINBLOCK using workloads based on public Ethereum traces (including smart contracts). We show that a single RAINBLOCK miner processes 27.4K txs per second (27× higher than a single Ethereum miner). In a geo-distributed setting with four regions spread across three continents, RAINBLOCK miners process 20K txs per second. 

FPGAs offer compelling acceleration opportunities for modern applications. However compilation for FPGAs is painfully slow, potentially requiring hours or longer. We approach this problem with a solution from the software domain: the use of a JIT. Code is executed immediately in a software simulator, and compilation is performed in the background. When finished, the code is moved into hardware, and from the user's perspective it simply gets faster. We have embodied these ideas in Cascade: the first JIT compiler for Verilog. Cascade reduces the time between initiating compilation and running code to less than a second, and enables generic printf debugging from hardware. Cascade preserves program performance to within 3× in a debugging environment, and has minimal effect on a finalized design. Crucially, these properties hold even for programs that perform side effects on connected IO devices. A user study demonstrates the value to experts and non-experts alike: Cascade encourages more frequent compilation, and reduces the time to produce working hardware designs.