Congestion-Aware CAD Optimizations for Routing-Constrained FPGAs
Bibliographic record
Abstract
Routing resources dominate FPGA area and have become more critical as logic scales faster than interconnect in recent technology nodes. The integration of high-bandwidth hardened blocks such as HBM and PCIe further increases routing demand, increasing the risk of routing congestion that can degrade quality of results (QoR) or cause routing failure. This work presents a computationally efficient heuristic to estimate routing channel demand during placement. Integrated into an open-source CAD flow, the estimator enables a congestion-aware placement algorithm that spreads blocks away from predicted hotspots. Despite the added complexity, the proposed algorithm converges faster, reducing placement time by 2.2%. On the Titan benchmark suite, the approach cuts routing time by 48% and critical path delay by 2.6%, with only 3% more wirelength. By improving routability in routing-constrained FPGAs, our method allows architects to reduce routing area or designers to achieve higher utilization without comnromising routability.
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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 | 0.001 |
| 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) | 0.001 | 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".