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Characterizing Serverless Workloads: A Large-Scale Analysis of Function-as-a-Service Platforms

Saman Akbari, Yassine Lazreg, Mohammadreza Malekabbasi, Manfred Hauswirth

Nov 3, 2026arXiv:2611.05081v1
cs.DCcs.PF
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Scorecard· 16/16
5.5/10 impact

Useful, timely consolidation of eight public FaaS traces with open code, but descriptive, largely confirmatory, and with confounded trend claims and unvalidated recommendations.

Abstract

Serverless computing is a popular approach to application deployment without having to manage the underlying infrastructure. Its most common implementation is Function-as-a-Service (FaaS), in which applications are structured as fine-grained functions. FaaS providers face non-trivial tasks in the management of their platforms, including cold starts, auto-scaling, and scheduling. The design of optimized platforms requires an accurate understanding of realistic serverless workloads. However, existing research and platforms rely on insights from single, often outdated datasets. In this work, we conduct a large-scale, cross-platform comparative analysis of eight publicly available FaaS workload traces from major cloud providers (Alibaba, Azure, Huawei, IBM) and a scientific computing platform (Globus). We provide a comprehensive and up-to-date view of the serverless ecosystem by characterizing key dimensions such as invocation patterns, latency, cold start behavior, and resource utilization. Our analysis shows that although invocation patterns remain universal, execution times have shortened, shifting the performance bottleneck toward platform scheduling and dependency management. We also observe an architectural shift toward "Serverless 2.0" models, where concurrent, long-lived containers are increasingly utilized to bypass cold start penalties. Furthermore, we found resource over-provisioning and extreme skew in user request volumes. These findings provide actionable insights for designing more efficient FaaS platforms, informing improved approaches to targeted cold start mitigation, predictive resource management, and dependency-aware scheduling.

AI Impact Assessments

(1 model)

Core Contribution

This is a cross-trace empirical characterization study. It analyzes eight public FaaS traces (Azure19/20/21, Alibaba21, Huawei23/25, Globus24, IBM26) along invocation patterns, burstiness, diurnal cycles, popularity skew, idle times, cold starts, latency and overhead, instances, resource usage and limits, runtimes, triggers, I/O, and per-user tenancy. Its main contribution is putting these previously siloed datasets side by side and distilling ten "insights" for platform design. The headline claims are:

  • Invocation patterns (diurnal cycles, extreme skew) are universal.
  • Execution times have shrunk to milliseconds ("nanoservices"), so scheduling and dependency deployment dominate overhead.
  • There is a shift toward "Serverless 2.0" (long-lived, concurrent containers with minimum scale), visible in IBM26.
  • Resources are widely over-provisioned.
  • Timer triggers are overtaking HTTP.
  • The novelty is synthesis and breadth, not new methods or new data. The code is open-sourced, which adds practical value.

    Methodological Rigor

    The analysis is descriptive and uses standard statistics: CDFs, percentiles, Lorenz curves, CV, and Spearman correlation. It uses Dask for scale and applies reasonable cleaning (dropped rows reported in Table 2). Several weaknesses limit the strength of the inferences:

  • Confounded temporal claims. Trends such as "execution times have shortened" and "Node.js → Java" compare different providers (Azure19 vs. Huawei/IBM), not the same platform over time. Platform effects, user populations, and trace construction (e.g., Huawei23 being internal and the "private" trace covering ~200 popular functions) are conflated with temporal evolution. The Limitations section admits black-box confounding but the headline narrative still reads causally.
  • Heterogeneous metrics. Execution time definitions, granularity (per-minute vs. per-invocation), and per-request vs. per-function aggregation differ across traces. Only a subset of traces supports each analysis (often 2–4), so "cross-platform" claims frequently rest on two datasets (e.g., runtimes: Alibaba21 vs. Huawei25; triggers: Azure19 vs. Huawei25).
  • Imputed data. Poisson approximation of sub-second arrivals for Huawei23/IBM26 is a strong assumption that directly drives the warm-start CDFs. Cold starts in IBM26 are inferred from pod creation beyond minimum scale. Negative overheads are clamped to zero.
  • Weak inferences. Spearman correlations on Globus24 (imports vs. response time) are used to conclude that dependencies are a better predictor than code size, with no control for endpoint type or queueing. The −0.84 correlation is computed on 24 hourly points. The "Serverless 2.0 shift" rests on a single IBM trace, which is a different product (Knative/Code Engine), not evidence of an industry-wide shift. The over-provisioning claim relies on Huawei traces and limits-vs-usage comparisons that ignore headroom and burst needs.
  • Generalization limits. The Globus24 vs. commercial contrasts are descriptive but not surprising.
  • Potential Impact

    The paper is useful as a reference and entry point for serverless systems researchers. It supplies a consolidated table of trace schemas and metrics, concrete numbers (cold start breakdowns, memory/CPU limit vs. usage, concurrency defaults), and an argument for multi-trace evaluation. That argument is the most actionable message: algorithms tuned on Azure19 may not transfer. The paper is likely to be cited in motivation sections and in work on keep-alive, pre-warming, autoscaling, and trace-based benchmarking. It will not change the field's direction. Most findings (diurnal patterns, skew, heavy tails, long-tail cold starts) confirm prior single-trace studies. The newer observations (IBM26 concurrency and minimum-scale behavior, timer-trigger share, millisecond execution) are mostly taken from the source trace papers. The "insights" are fairly generic recommendations (per-function keep-alive, right-sizing, dependency-aware scheduling) and are not validated by experiments or simulation.

    Timeliness & Relevance

    It is timely. Serverless research leans heavily on the aging Azure19 trace, and several new traces have appeared recently (Huawei25, IBM26, Globus24). A consolidated view is a real community need, and the "Serverless 2.0" framing is topical. The value depends on trace availability, and the paper is a snapshot that will age as new traces appear. It proposes a common trace format but does not deliver one.

    Strengths

  • Broadest comparative coverage of public FaaS traces to date.
  • Clear structure, with numbered insights and tables that make results easy to look up.
  • Open-sourced analysis code, with public datasets, so it is highly reproducible.
  • Candid limitations section.
  • Useful per-request vs. per-function distinctions (e.g., Huawei25 cold-start rate 0.02% vs. >80%), which show how misleading aggregate metrics can be.
  • Limitations

  • No new data, methods, or validated optimizations. The recommendations are untested.
  • Uneven trace coverage means many sections are two-trace comparisons.
  • Temporal trend claims are confounded with platform and population differences.
  • Heavy reliance on imputation and assumptions for some key figures.
  • Shallow causal analysis (black-box platforms, with policy and workload effects entangled).
  • Some sections read like catalogs of statistics, with limited explanatory modeling.
  • Overlaps with the source trace papers for many of the numbers.
  • Overall

    This is a solid, useful, but incremental measurement and synthesis paper. It is likely to be a handy reference with moderate citation impact in the serverless and cloud systems community, but with limited conceptual novelty or surprise.

    Rating:5.5/ 10
    Significance 5.5Rigor 5Novelty 4Clarity 7.5

    Generated Nov 4, 2026

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