GPU-Accelerated Wire-Length Estimation for FPGA Placement
Bibliographic record
Abstract
In the FPGA design flow, placement remains one of the most time-consuming stages, and is also crucial in terms of quality of result. HPWL and Star+ are widely used as cost metrics in FPGA placement for estimating the total wire-length of a candidate placement prior to routing. However, both wire-length models are expensive to compute requiring O(nm) time, where n is the number of nets and m is the average net cardinality. This paper proposes using the massively multi-threaded architecture provided by GPUs to reduce the time required to compute HPWL and Star+. First, a specialized set of data structures is developed for storing net-connectivity information on the GPU. Next, a study is performed to determine how to best map the data structures onto the GPU to exploit the heterogeneous memories and thread-level parallelism that are available. Finally, a study is performed to determine what effect circuit size and net cardinality have on the speedups that can be achieved. Overall, the results show that speedups of as much as 160x over a serial CPU implementation can be achieved for both models when tested using standard benchmarks.
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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".