Probing the Testing Surface: How Three Bash Commands Shaped the cuzk Proving Daemon

Introduction

In the midst of designing a pipelined SNARK proving daemon called cuzk, an assistant sat down at a terminal and ran three --help commands. The output—three usage screens for lotus-bench simple commit2, lotus-bench simple window-post, and lotus-bench simple provereplicaupdate1—appears at first glance to be a mundane piece of exploration. Yet this single message, <msg id=81>, represents a critical juncture in a much larger architectural investigation. It is the moment where abstract design meets concrete reality: where the assistant verified that the testing infrastructure needed to validate a new proving daemon actually exists, and where the precise contours of that infrastructure were mapped for the first time.

This article unpacks that message in depth: why it was written, what decisions it enabled, what assumptions it carried, and how its output knowledge directly shaped the cuzk-project.md document that was the session's ultimate deliverable. To understand this message is to understand a key phase of systems research—the phase where a developer stops reasoning from first principles and starts interrogating the actual tools at hand.

Context: The cuzk Project and the Need for Testing Infrastructure

The broader session (Segment 3 of a multi-segment investigation) was dedicated to designing cuzk, a pipelined SNARK proving daemon inspired by GPU inference engine architectures like vLLM, Triton, and TensorRT-LLM. The core insight was that Groth16 proof generation—specifically the SUPRASEAL_C2 pipeline for Filecoin's Proof-of-Replication (PoRep), WindowPoSt, and SnapDeals—exhibits structural parallels to large language model inference: both involve loading large parameter sets (SRS parameters vs. model weights), processing input vectors (witnesses vs. token sequences), and executing compute-heavy kernels (NTT/MSM vs. attention/MLP). The cuzk daemon aimed to apply inference-engine patterns—persistent model loading, request scheduling, batch accumulation, memory pooling—to the proving domain.

But before any architecture could be committed to a design document, the assistant needed to answer a fundamental question: What testing infrastructure already exists, and can it be repurposed?

The user's instructions in <msg id=78> were explicit: "for pre-curio phases also build a util that allows for single/batch/etc testing with easier setup." This meant the cuzk project needed a testing utility (cuzk-bench) that could generate proofs without requiring the full Curio orchestration layer. The natural candidate was lotus-bench, the benchmarking tool shipped with the Lotus Filecoin implementation. But the assistant needed to verify that lotus-bench supported the specific proof types cuzk would need to handle, and to understand the exact command-line interfaces.

Messages <msg id=79> and <msg id=80> had already established the lay of the land: the golden test data in /data/32gbench/ (including C1 outputs, cache directories, and commitment digests for a 32 GiB sector), and the top-level lotus-bench simple help showing the available subcommands. Message <msg id=81> drills down into three specific subcommands, each corresponding to a distinct proof type that cuzk would need to support.

The Message Itself: Three Commands, Three Proof Types

The message consists of three bash invocations, each querying the --help flag of a lotus-bench simple subcommand. Let us examine each in turn.

commit2: The PoRep C2 Pipeline

~/lotus/lotus-bench simple commit2 --help
NAME:
   lotus-bench simple commit2

USAGE:
   lotus-bench simple commit2 [command options] [c1out.json]

OPTIONS:
   --no-gpu            disable gpu usage for the benchmark run (default: false)
   --miner-addr value  pass miner address (only necessary if using existing sectorbuilder) (default: "t01000")
   --synthetic         generate synthetic PoRep proofs (default: false)
   --non-interactive   generate NI-PoRep proofs (default: false)

This is the command that drives the Groth16 proof generation for PoRep—the very pipeline that had been the subject of the previous seven optimization proposals. The commit2 subcommand takes a single input file (c1out.json), which is the output of the PreCommit2 phase. The assistant had already discovered C1 output files in /data/32gbench/: c1.json (51 MB), c1-single.json (48 MB), and c1-8p.json (384 MB). These files contain the intermediate computation results—the a/b/c vectors, the circuit evaluation outputs—that feed into the C2 prover.

The options reveal important dimensions of the testing space:

• --no-gpu: Allows CPU-only testing, critical for development environments without GPU access.
• --synthetic: Generates synthetic PoRep proofs, useful for benchmarking without real sector data.
• --non-interactive: Generates NI-PoRep (Non-Interactive Proof-of-Replication) proofs, a newer variant.
• --miner-addr: Associates the proof with a miner address, needed when using existing sectorbuilder state. For the cuzk testing utility, this command provides a clean entry point: feed it a C1 JSON file, get back a Groth16 proof. The simplicity of the interface (one positional argument, four optional flags) makes it ideal for the "single proof" test case in cuzk-bench.

window-post: The WindowPoSt Challenge

~/lotus/lotus-bench simple window-post --help
NAME:
   lotus-bench simple window-post

USAGE:
   lotus-bench simple window-post [command options] [sealed] [cache] [comm R] [sector num]

OPTIONS:
   --sector-size value  size of the sectors in bytes, i.e. 32GiB (default: "512MiB")
   --miner-addr value   pass miner address (only necessary if using existing sectorbuilder) (default: "t01000")

WindowPoSt (Window Proof-of-Spacetime) is a fundamentally different proof type from PoRep. Rather than proving that a sector was sealed correctly, WindowPoSt proves that a sector continues to be stored over time. The command signature reflects this: it takes a sealed sector file, a cache directory, a commitment digest (comm R), and a sector number. The --sector-size option defaults to 512 MiB but can be set to 32 GiB for the golden test data.

This command is more complex to drive from a testing utility because it requires actual sector data on disk—the sealed file and cache directory. The assistant had already confirmed the existence of these files in /data/32gbench/cache/, including the 32 GiB data-layer files and the p_aux metadata file. The comm R value was also available from /data/32gbench/commdr.txt.

The key insight here is that WindowPoSt testing requires more setup than commit2 testing. The cuzk-bench utility would need to handle this asymmetry, perhaps by providing higher-level wrappers that locate the correct files based on sector size and number.

provereplicaupdate1: The SnapDeals Update Path

~/lotus/lotus-bench simple provereplicaupdate1 --help
NAME:
   lotus-bench simple provereplicaupdate1

USAGE:
   lotus-bench simple provereplicaupdate1 [command options] [sealed] [cache] [update] [updatecache] [sectorKey] [newSealed] [newUnsealed] [vproofs.json]

OPTIONS:
   --sector-size value  size of the sectors in bytes, i.e. 32GiB (default: "512MiB")
   --miner-addr value   pass miner address (only necessary if using existing sectorbuilder) (default: "t01000")

SnapDeals (the Filecoin upgrade mechanism) introduces yet another proof type: ProveReplicaUpdate. This command has the most complex signature of the three, with seven positional arguments: the original sealed sector, its cache, the update data, the update cache, the sector key, the new sealed output, the new unsealed output, and a verification proofs JSON file.

The assistant had already discovered the corresponding test data in /data/32gbench/updatecache/ and /data/32gbench/updatecache-curio/, including the 64 GiB sc-02-data-tree-d.dat file and the tree-R files. The complexity of this command's interface signals that SnapDeals testing will be the most involved to automate in cuzk-bench.

Why This Message Matters: The Epistemology of Systems Design

At a surface level, <msg id=81> is simply three help screens. But in the context of the cuzk project, this message serves several profound functions.

Grounding Abstraction in Reality

The cuzk architecture document being written was necessarily abstract: it described gRPC APIs, SRS memory managers, priority schedulers, and GPU worker pipelines. But every abstraction must eventually be validated against concrete interfaces. By running these --help commands, the assistant was performing a reality check: Does the testing infrastructure I'm assuming actually exist? Does it work the way I think it does?

The discovery that commit2 takes a single JSON file, while provereplicaupdate1 takes seven positional arguments, immediately informs the design of the testing utility. A naive "one-size-fits-all" test harness would be impossible; instead, cuzk-bench would need proof-type-specific subcommands or wrappers. This realization is captured in the final cuzk-project.md document, which defines concrete cuzk-bench commands for each proof type.

Mapping the Proof-Type Landscape

The three commands correspond to the three proof families that Curio (the Filecoin mining orchestration layer) must handle:

1. PoRep (via commit2): Generated during sector sealing, the most compute-intensive proof.
2. WindowPoSt (via window-post): Generated periodically to prove continued storage.
3. SnapDeals (via provereplicaupdate1): Generated during sector upgrades. Each has different resource profiles, different circuit sizes, and different input data requirements. The cuzk scheduler would need to handle all three, potentially with different priority levels and resource allocations. By enumerating these commands, the assistant was implicitly defining the scope of the cuzk daemon: it must support at least these three proof types, and its testing infrastructure must be able to generate reference proofs for each.

Discovering Hidden Complexity

The --synthetic and --non-interactive flags on commit2 reveal a dimension of the proof system that might otherwise have been overlooked. Synthetic PoRep and NI-PoRep are variants with different circuit structures and different SRS parameter requirements. If the assistant had not run this --help command, the cuzk design might have assumed only standard PoRep, missing the need to support these variants.

Similarly, the --no-gpu flag on commit2 signals that CPU-based proof generation is possible, even if slow. This is valuable for the cuzk testing strategy: integration tests can run on CPU-only CI machines, while performance benchmarks use GPU hardware.

Assumptions Embedded in the Investigation

The assistant's exploration carries several assumptions worth examining:

That lotus-bench is the correct testing substrate. This assumption is reasonable given the user's explicit suggestion to "use or extend ~/lotus/lotus-bench simple .. commands." However, it implicitly assumes that lotus-bench produces proofs compatible with the cuzk daemon's expected output format. If the proof format changes between Lotus versions, the test data could become stale.

That the golden test data in /data/32gbench/ is sufficient. The assistant assumes that the existing C1 outputs, cache directories, and commitment digests can be fed directly into these commands to produce valid proofs. This is likely true, but it assumes the data was generated with compatible parameters (sector size, proof type, etc.).

That the command-line interfaces are stable. The --help output represents a snapshot of the current Lotus build. If the CLI changes in future versions, the cuzk-bench utility would need to adapt.

That the proof types are independent. The assistant treats each command as a separate testing pathway. But in production, Curio might chain these proofs together or share state between them. The cuzk design would need to account for these interactions at the orchestration layer, even if the testing utility treats them separately.

Input Knowledge Required

To fully understand <msg id=81>, a reader needs:

1. Knowledge of Filecoin proof types: Understanding what PoRep, WindowPoSt, and SnapDeals are, and why each requires different proving machinery.
2. Familiarity with the SUPRASEAL_C2 pipeline: The Groth16 proof generation flow, including the C1→C2 handoff and the role of SRS parameters.
3. Context from previous exploration: The discovery of golden test files in <msg id=79> and <msg id=80>, including the C1 JSON files and cache directories.
4. Understanding of the cuzk project goals: That this is a pipelined proving daemon inspired by GPU inference engines, and that the testing utility is a prerequisite for development.
5. Knowledge of the Lotus codebase: Specifically the lotus-bench tool and its simple subcommand hierarchy.

Output Knowledge Created

This message produces several concrete pieces of knowledge:

1. Exact CLI signatures for three proof types: The positional arguments and option flags for commit2, window-post, and provereplicaupdate1.
2. Default values for key options: --no-gpu defaults to false, --sector-size defaults to 512 MiB, --miner-addr defaults to "t01000".
3. Proof-type complexity hierarchy: commit2 is simplest (one input), window-post is moderate (four inputs), provereplicaupdate1 is most complex (seven inputs).
4. Available proof variants: The --synthetic and --non-interactive flags for PoRep.
5. GPU dependency model: commit2 has an explicit --no-gpu flag, while window-post and provereplicaupdate1 do not, suggesting different GPU requirements. This knowledge directly feeds into the cuzk-project.md document's "Testing and Benchmarking" section, where concrete cuzk-bench commands are specified for each proof type.

The Thinking Process: A Window into Systematic Investigation

The assistant's reasoning, while not explicitly stated in <msg id=81>, is visible in the sequence of commands and the choices made:

Why these three commands? The assistant could have explored many other lotus-bench simple subcommands (addpiece, precommit1, precommit2, etc.). The selection of commit2, window-post, and provereplicaupdate1 is deliberate: these are the three proof-generation commands, as opposed to the sealing/preparation commands. The cuzk daemon is a proving daemon—it generates Groth16 proofs, not sealed sectors. The assistant correctly identifies the subset of commands relevant to the project's scope.

Why not explore options more deeply? The --help output shows only the option names and defaults, not their semantics or valid values. The assistant could have run additional commands to probe each option (e.g., --synthetic with different values). The decision to stop at --help suggests a cost-benefit calculation: the help text provides enough information for the design document, and deeper exploration can happen during implementation.

What about error cases? The assistant does not test what happens when invalid arguments are provided, or when the golden data is incompatible with the command's expectations. This is appropriate for the design phase; error handling will be explored during implementation.

The ordering of commands is also informative: commit2 first (the core PoRep command, most relevant to the optimization proposals), then window-post (a different proof type), then provereplicaupdate1 (the most complex). This reflects a prioritization from most-important to most-complex.

Connection to the Broader Architecture

The knowledge from <msg id=81> ripples through the cuzk architecture in several ways:

The SRS Memory Manager: Different proof types require different SRS parameter sets. The --synthetic flag on commit2 might use a different parameter file than standard PoRep. The cuzk SRS memory manager's hot/warm/cold tiering must account for these variations.

The Scheduler: The complexity differences between proof types (commit2's single input vs. provereplicaupdate1's seven inputs) affect scheduling decisions. A batch of SnapDeals proofs will have higher I/O overhead than a batch of PoRep proofs.

The GPU Worker Pipeline: The presence of --no-gpu on commit2 but not on the other commands suggests that GPU acceleration is more critical for PoRep than for WindowPoSt or SnapDeals. This could influence GPU allocation policies in the worker pipeline.

The Testing Utility: The cuzk-bench tool must wrap each of these commands with appropriate argument handling. The design document specifies commands like cuzk-bench commit2 --c1out /data/32gbench/c1.json and cuzk-bench window-post --sealed /data/32gbench/sealed --cache /data/32gbench/cache --comm-r ....

Conclusion

Message <msg id=81> is a deceptively simple piece of systems investigation. On its surface, it is three help screens from a benchmarking tool. But in the context of designing a complex proving daemon, it represents a critical grounding exercise—a moment where abstract architectural thinking meets concrete operational reality.

The assistant's systematic exploration of lotus-bench simple subcommands reveals the contours of the testing landscape: the simplicity of PoRep proof generation, the moderate complexity of WindowPoSt, and the baroque interface of SnapDeals updates. Each command tells a story about the proof type it serves, the data it requires, and the computational resources it consumes.

This message also exemplifies a key skill in systems engineering: knowing when to stop reasoning from first principles and start interrogating the actual tools. The cuzk architecture could have been designed entirely from theoretical considerations, but it would have been built on assumptions that might not hold. By running these three --help commands, the assistant replaced assumptions with facts—and those facts shaped the design document that would guide the next 18 weeks of implementation.

In the end, <msg id=81> is a testament to the value of empirical investigation in systems design. The three help screens, taken together, are not just documentation—they are the foundation upon which the cuzk proving daemon was built.