On the Evaluation of Dense Chip-Multiprocessor Architectures
Bibliographic record
Abstract
Chip-multiprocessors (CMPs) have been revealed as the most promising way of making efficient use of current improvements in integration scale. Nowadays, commercial CMP releases integrate at most 8 processor cores onto the chip. However, 16 or more processor cores are expected to be offered in near future dense-CMP (D-CMP) systems. In this way, these architectures impose new design restrictions, and some topics, such as the cache-coherence problem, must be reviewed. In this paper we present an exhaustive performance evaluation of two recently proposed D-CMP architectures, making special emphasis on the solution to the cache-coherence problem that each one of them introduces. The shared bus fabric architecture (SBF) features a snoop cache-coherence protocol and is based on a high-performance bus fabric interconnection network. The second architecture follows a directory-based approach and integrates a bi-dimensional mesh as the interconnection network. Our results show that the performance achieved by the SBF architecture is hard-limited by the bandwidth restrictions of the bus fabric. On the other hand, the directory-based architecture outperforms the SBF one, but presents some performance inefficiencies due to the additional indirection that the directory structure stored in the L2 cache level introduces
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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 | 0.001 | 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".