TapeFlow: Streaming Gradient Tapes in Automatic Differentiation
Bibliographic record
Abstract
Computing gradients is a crucial task in many domains, including machine learning, physics simulations, and scientific computing. Automatic differentiation (AD) computes gradients for arbitrary imperative code. In reverse mode AD, an auxiliary structure, the tape, is used to transfer intermediary values required for gradient computation. The challenge is how to organize the tape in the memory hierarchy since it has a high reuse distance, lacks temporal locality, and inflates working set by 2-4×. We introduce Tapeflow, a compiler framework to orchestrate and manage the gradient tape. We make three key contributions. i) We introduce the concept of regions, which transforms the tape layout into an array-of-structs format to improve spatial reuse. ii) We schedule the execution into layers and explicitly orchestrate the tape operands using a scratchpad. This reduces the required cache size and on-chip energy. iii) Finally, we stream the tape from the DRAM by organizing it into a FIFO of tiles. The tape operands arrive just-in-time for each layer. Tapeflow, running on the same hardware, outperforms Enzyme, the state-of-the-art compiler, by 1.3-2.5×, reduces on-chip SRAM usage by 5–40 ×, and saves 8× on-chip energy. We demonstrate Tapeflow on a wide range of algorithms written in general-purpose language.
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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".