Implementation of a Configurable Crossbar Switch for Prototyping of Single-Chip Multiprocessors
Bibliographic record
Abstract
This paper describes the implementation of a configurable crossbar switch for use as an interconnect between custom processors and cache/memory components in research prototyping of tightly-coupled single-chip multiprocessors in programmable logic. The configurability of the crossbar includes the number of ports and their width, the provision of buffering at the ports, and the complexity of the arbitration. Configuration parameters control the size of the full expansion of the crossbar from a structured, generic specification in VHDL. Results from synthesizing crossbar instances with custom 32-bit pipelined processors that have been developed in earlier multiprocessor research efforts of Manjikian (2003) are presented for configurations ranging in size from 2 × 2 to 16 × 16. With 32-bit paths for address and data, the prototyping overhead of the interconnect/arbitration logic relative to processor logic ranges from 1.2% for a 2 × 2 configuration to 55% for a large 16 × 16 configuration. For a 16 × 16 system, in particular, the crossbar and processor logic consume 73% of the logic resources in a high-capacity Altera Stratix 1S80 chip, with ample resources still available in this large chip for other components. Operational results are also provided to demonstrate the functionality of the crossbar in providing concurrent service of cache misses from multiple processors.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one teacher head, not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".