Dooly: Configuration-Agnostic, Redundancy-Aware Profiling for LLM Inference Simulation
Reviewed by Pith T0 review T1 audit T2 compute T3 formal T4 kernel 2026-05-22 10:17 UTCgrok-4.3pith:XC46HSFBrecord.jsonopen to challenge →
The pith
Dooly profiles LLM operations once across configurations by tracking dimension origins, cutting profiling GPU hours by 56 percent while keeping simulation errors under 8 percent.
A machine-rendered reading of the paper's core claim, the machinery that carries it, and where it could break.
Core claim
Dooly performs one inference pass, labels every input dimension of each operation with its source via taint propagation, isolates stateful kernels such as attention by reusing the engine's own initialization code, and selectively profiles only operations missing from its latency database; the database then supplies regression models that replace the profiling step inside any existing simulator.
What carries the argument
Taint propagation during a single inference pass to classify fixed versus request-dependent dimensions, feeding a selective latency database that skips redundant profiles.
If this is right
- Existing simulators gain a drop-in backend that supports rapid sweeps over hardware, engines, and backends.
- Profiling cost grows with the number of distinct request sizes rather than the number of full model configurations.
- The same database serves multiple attention backends and GPU platforms without per-combination restarts.
- Stateful operations like attention require no custom instrumentation beyond the engine's standard setup.
Where Pith is reading between the lines
- Public release of the latency database could let new models start from partial results instead of zero.
- The dimension-labeling step might transfer to simulators for other layered models that share similar input structures.
- Runtime systems could consult the same models to pick configurations on the fly as request patterns change.
Load-bearing premise
That model-configuration values such as head size and layer count recur across architectures so one sweep over request-dependent dimensions covers all of them.
What would settle it
A new model whose configuration values are entirely distinct from prior ones, forcing a complete re-profiling run instead of database reuse.
Figures
read the original abstract
Selecting the optimal LLM inference configuration requires evaluation across hardware, serving engines, attention backends, and model architectures, since no single choice performs best across all workloads. Profile-based simulators are the standard tool, yet they hardcode their operation set to a specific configuration and re-profile every operation from scratch, making exploration prohibitively expensive. This cost stems from a missing structural understanding: every input dimension of each operation is fixed by the model configuration or determined by the incoming request. Many model-configuration values (e.g., head size, layer count) recur across models, so the same operation runs in many configurations; a single sweep over the request-dependent dimensions can serve them all. We present Dooly, which exploits this structure to achieve configuration-agnostic, redundancy-aware profiling. Dooly performs a single inference pass, labels each input dimension with its origin via taint propagation, and selectively profiles only operations absent from its latency database; stateful operations such as attention are isolated by reusing the serving engine's own initialization code, eliminating manual instrumentation. It builds latency regression models based on the database, which becomes a drop-in backend for existing simulators. Across two GPU platforms, three attention backends, and diverse model architectures, Dooly achieves simulation accuracy within 5% MAPE for TTFT and 8% for TPOT while reducing profiling GPU-hours by 56.4% across 12 models compared to the existing profiling approach. We have open-sourced Dooly at https://github.com/dooly-project.
Editorial analysis
A structured set of objections, weighed in public.
Referee Report
Summary. The manuscript presents Dooly, a profiling system for LLM inference simulation. It performs a single inference pass with taint propagation to label each operation's input dimensions as either fixed by the model configuration or determined by the incoming request. This enables selective profiling of only absent operations (with stateful attention isolated via the serving engine's initialization code), construction of a latency database, and regression models that serve as a drop-in backend for existing simulators. The central empirical claim is that, across two GPU platforms, three attention backends, and 12 models, the approach yields simulation accuracy within 5% MAPE for TTFT and 8% for TPOT while cutting profiling GPU-hours by 56.4% relative to conventional per-configuration profiling.
Significance. If the accuracy and cost-reduction claims hold under independent verification, the work would meaningfully lower the expense of configuration exploration for LLM serving, particularly when sweeping across hardware, engines, and backends. The open-sourcing of the implementation is a concrete strength that supports reproducibility and adoption.
major comments (2)
- [Abstract and §5] Abstract and §5: the reported 56.4% GPU-hour reduction and 5%/8% MAPE figures are presented without explicit description of experimental controls, baseline implementation details, data exclusion criteria, or how the 12-model corpus was selected. These omissions are load-bearing for the central performance claim because post-hoc choices could materially affect the measured savings.
- [§3.2] §3.2 (Taint Propagation): the mechanism for labeling dimensions is described at a high level but does not address potential failure modes in stateful or custom kernels (e.g., dynamic KV-cache shapes, padding logic, or tensor views inside FlashAttention/xFormers). If taint tracking misses indirect or runtime-determined dimensions, the resulting latency database would contain gaps or duplicates, directly undermining both the reported reduction and the regression accuracy.
minor comments (2)
- [§4.1] §4.1: the regression model formulation would benefit from an explicit equation showing how the latency database is mapped to predicted TTFT/TPOT values.
- [Table 2] Table 2: the per-model breakdown of profiled operations would be clearer with an additional column indicating the fraction of operations that were reused from prior configurations.
Simulated Author's Rebuttal
We thank the referee for their constructive comments. We address each major comment below and have revised the manuscript to provide the requested details on experimental controls and to expand the discussion of taint propagation limitations.
read point-by-point responses
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Referee: [Abstract and §5] Abstract and §5: the reported 56.4% GPU-hour reduction and 5%/8% MAPE figures are presented without explicit description of experimental controls, baseline implementation details, data exclusion criteria, or how the 12-model corpus was selected. These omissions are load-bearing for the central performance claim because post-hoc choices could materially affect the measured savings.
Authors: We agree that the manuscript would benefit from greater transparency on these points. In the revised version we have inserted a new subsection §5.1 that explicitly states: the baseline is the conventional per-configuration profiler that re-profiles every operation for each (model, hardware, backend) tuple; no profiling runs were excluded from the reported averages; GPU-hours were measured directly with nvidia-smi on the two evaluated platforms; and the 12-model corpus was assembled to span decoder-only and encoder-decoder families, parameter counts from 1 B to 70 B, and the three attention backends under test. These additions make the 56.4 % reduction and accuracy numbers directly reproducible and remove any ambiguity about post-hoc selection. revision: yes
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Referee: [§3.2] §3.2 (Taint Propagation): the mechanism for labeling dimensions is described at a high level but does not address potential failure modes in stateful or custom kernels (e.g., dynamic KV-cache shapes, padding logic, or tensor views inside FlashAttention/xFormers). If taint tracking misses indirect or runtime-determined dimensions, the resulting latency database would contain gaps or duplicates, directly undermining both the reported reduction and the regression accuracy.
Authors: We appreciate the referee’s focus on this potential weakness. The taint tracker operates on PyTorch tensor metadata and therefore observes the concrete runtime shapes that reach each kernel, including those produced by padding and view operations. Stateful attention is deliberately excluded from the profiled path by reusing the serving engine’s own initialization code, as already noted in §3.2. Nevertheless, we acknowledge that highly opaque third-party kernels could in principle hide indirect dependencies. The revised §3.2 now contains an explicit limitations paragraph that describes this edge case and states our mitigation: any operation whose input dimensions cannot be fully classified falls back to conventional per-configuration profiling. Our evaluation across three distinct attention backends produced no such fallbacks, supporting the reported savings and accuracy. revision: yes
Circularity Check
No significant circularity; empirical claims rest on external measurements
full rationale
The paper describes an empirical profiling system that uses taint propagation on a single inference pass to classify operation input dimensions as model-configuration-fixed or request-determined, then selectively profiles only missing operations and fits latency regression models. Central claims of 5% MAPE TTFT / 8% TPOT accuracy and 56.4% GPU-hour reduction are obtained by running the resulting simulator against actual inference timings across 12 models, two GPU platforms, and three attention backends. No equation or derivation reduces to a fitted parameter renamed as a prediction, no self-citation supplies a load-bearing uniqueness theorem, and the validation data are independent of the profiling database used to train the regressions. The approach is therefore self-contained against external benchmarks.
Axiom & Free-Parameter Ledger
axioms (1)
- domain assumption Every input dimension of each operation is fixed by the model configuration or determined by the incoming request.
Lean theorems connected to this paper
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IndisputableMonolith/Foundation/AbsoluteFloorClosure.leanabsolute_floor_iff_bare_distinguishability unclear?
unclearRelation between the paper passage and the cited Recognition theorem.
Dooly performs a single inference pass, labels each input dimension with its origin via taint propagation, and selectively profiles only operations absent from its latency database
-
IndisputableMonolith/Foundation/BranchSelection.leanbranch_selection unclear?
unclearRelation between the paper passage and the cited Recognition theorem.
Signature generation... operation name and the values of its MODEL_CONFIG-tainted dimensions... set of GPU kernel symbols... digest of the module instance’s primitive Python attributes
What do these tags mean?
- matches
- The paper's claim is directly supported by a theorem in the formal canon.
- supports
- The theorem supports part of the paper's argument, but the paper may add assumptions or extra steps.
- extends
- The paper goes beyond the formal theorem; the theorem is a base layer rather than the whole result.
- uses
- The paper appears to rely on the theorem as machinery.
- contradicts
- The paper's claim conflicts with a theorem or certificate in the canon.
- unclear
- Pith found a possible connection, but the passage is too broad, indirect, or ambiguous to say the theorem truly supports the claim.
Reference graph
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