DTSVLIW : VLIW Performance with Sequential Code

Due to the temporal execution locality present in programs, even small instruction caches (16-Kbyte) can provide processors with fast access to instructions most of the time. The Dynamically Trace Scheduled VLIW (DTSVLIW) architecture exploits programs’ temporal execution locality by executing code in two distinct modes. In the first execution encounter, fragments of the code are executed in sequential mode (in a simple pipelined processor), scheduled into blocks of VLIW instructions and cached in a VLIW cache by the DTSVLIW’s Scheduler Engine. In subsequent encounters, the DTSVLIW’s VLIW Engine executes these blocks in VLIW mode. In this paper, we present experiments which show that DTSVLIW machines can perform better than Superscalar machines with equivalent hardware and better than VLIWs with the same degree of parallelism, while keeping the fast clock of the latter. We also discuss how the DTSVLIW compares with the Trace Cache and EPIC architectures.