---

name: sosp-experiments description: Use when designing or auditing the evaluation of a SOSP paper — mapping every claim to an experiment, choosing baselines a systems PC will accept as fair, mixing microbenchmarks with end-to-end and failure runs, reporting tails and overheads honestly, and isolating the mechanism the design credits.

SOSP Experiments

Use this while the evaluation is being designed — it determines whether the paper is writable at all. SOSP reviews concentrate their negative weight on evaluation soundness, and the venue's response phase forbids new experiments (CFP, 2026 cycle, checked 2026-07-08), so a hole discovered in review stays a hole. The evaluation's job is to make each claim's evidence findable, fair, and attributable to the mechanism the paper credits.

Claims first, experiments second

Write the claim list before designing runs; every evaluation subsection should open by naming the claim it discharges.

Claim type	Required evidence	Classic hole
"Foo improves throughput/latency"	End-to-end runs vs tuned state-of-the-art baselines, real + synthetic workloads	Baseline in default config while Foo is hand-tuned
"The gain comes from mechanism M"	Ablation: Foo with M disabled, or M grafted onto the baseline	Whole-system win credited to one component on faith
"Overhead is acceptable"	Cost measured where it hurts: memory, CPU, write amplification, the workload M does not help	Only the favorable workload reported
"Foo survives failures"	Kill/partition/restart runs with recovery-time distributions	Availability claimed, only steady state measured
"Foo scales"	Sweep to the knee, with the bottleneck at the knee identified	Straight-line plot ending before saturation
"Correctness holds under concurrency"	Stress + targeted schedules, or a verification argument	"We ran it for days"

Baselines a systems PC accepts

• Compare against the published state of the art, not only your own strawman variants; if the strongest system is unrunnable (dead code, unobtainable hardware), say so in the paper and compare against its published numbers with the configuration deltas spelled out.
• Tune the baseline with the same care as your system, and document both tunings. "We used X's defaults" invites the PC member who built X to explain what the defaults are for.
• Match the fairness surface: same kernel, same mitigations, same NIC firmware, same warm-up policy. An OS-level artifact changes the platform under everything, so baseline runs need the environment pinned too (see sosp-reproducibility).

Workloads: three layers, each with a job

1. Microbenchmarks isolate mechanisms and expose costs; they prove why.
2. Application-level or end-to-end workloads (real applications on top of the system) prove the why matters; a syscall-path win that vanishes under a real application is a finding, not a failure to report.
3. Trace-driven runs on production or public traces prove relevance; when the trace is private, characterize it and pair it with a matched synthetic generator (the tiering that artifact evaluation later formalizes).

Tails, variance, and the numbers reviewers check first

Systems effects live in distributions, and SOSP reviewers reach for the tail:

• Report p50/p99 (p999 where the claim warrants) with repetition counts and spread; a single-run p99 will be called folklore.
• State the load point for every latency number — latency without offered load is meaningless, and latency-throughput curves beat point pairs.
• Account for the denominator: speedups over a baseline that is itself misconfigured are the fastest way to lose the room at the PC meeting.

Evaluation matrix (one row per claim; freeze before the writing sprint)

claim                      experiment            workload/trace     baseline+tuning   metric+spread      figure
throughput at scale        e2e sweep to knee     YCSB-B + trace T1  X v2.3 tuned §6.1 ops/s, 5 runs, CI  Fig 6
gain attributable to M     ablation Foo-noM      YCSB-B             Foo itself        delta ops/s        Fig 7
recovery independent of    kill @ 3 log sizes    trace T1           X                 p50/p99 recov, 10x Fig 9
  log size
overhead where M is idle   read-only run         YCSB-C             X                 CPU%, mem, 5 runs  Tab 4

Honesty as a strategy

The evaluation section is also where credibility is banked for the PC meeting. Report the workload where the design loses, and explain the regime boundary — a measured loss with a mechanism story reads as understanding; a suspiciously uniform sweep of wins reads as curation. Reviewers at this venue have written these sections themselves; the fastest way to earn a champion is an evaluation that anticipates the attack they were about to write.

Output format

[Claim map] every paper claim -> experiment row? orphans: <list>
[Baseline audit] SOTA present? tuning documented both sides?
[Layer coverage] micro / end-to-end / trace — gaps
[Tail discipline] spreads + load points on all latency numbers?
[Attribution] ablations isolate the credited mechanism?
[Adverse results] where the design loses + is it in the paper?