A Resource-Shared VLIW Processor for Low-Power On-Chip Multiprocessing in the Nanometer Era

Kazutoshi KOBAYASHI  Masao ARAMOTO  Hidetoshi ONODERA  

Publication
IEICE TRANSACTIONS on Electronics   Vol.E88-C   No.4   pp.552-558
Publication Date: 2005/04/01
Online ISSN: 
DOI: 10.1093/ietele/e88-c.4.552
Print ISSN: 0916-8516
Type of Manuscript: Special Section PAPER (Special Section on Low-Power LSI and Low-Power IP)
Category: Digital
Keyword: 
parallel processing,  VLIW,  SMT,  low power,  nanometer,  leakage power,  

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Summary: 
We propose a low-power resource-shared VLIW processor (RSVP) for future leaky nanometer process technologies. It consists of several single-way independent processor units (IPUs) that share parallel processor resources. Each IPU works as a variable-way VLIW processor sharing the parallel resources according to priorities of given tasks. RSVP allocates shared parallel resources to the IPUs cycle by cycle. It can minimize the number of NOPs that is wasting power. The performance per power (P3) of a 4-parallel 4-way RSVP that corresponds to four 4way VLIWs is 3.7% better than a conventional 4-parallel 4-way VLIW multiprocessor in the current 90 nm process. We estimate that the RSVP achieves 36% less leakage power and 28% better P3 in the future 25 nm process. We have fabricated an RSVP test chip that contains two IPU and a shared resource equivalent to two 2way VLIWs in a 180 nm process. It is functional at 100 MHz clock speed and its power is 130 mW.