dev-benchmark

Automate Capsem performance benchmarking in a VM and output JSON reports.

68|10|Updated Sep 26, 2025
One-click install
npx skills add https://github.com/google/capsem --skill dev-benchmark
Or copy as Structured Prompt for Agent
Please help me install this Agent Skill.
Skill: dev-benchmark
Source: https://github.com/google/capsem/tree/main/skills/dev-benchmark
Command: npx skills add https://github.com/google/capsem --skill dev-benchmark

SYSTEM DOCUMENTATION & REQUIREMENTS

What problem does it solve?

Capsem benchmarking helps developers measure performance characteristics of Capsem components inside isolated VMs, enabling detection of regressions and validation of optimizations before release.

Core Features & Use Cases

  • 7 benchmark categories: disk, rootfs, startup, http, throughput, snapshot, and all, covering a broad performance spectrum.
  • JSON output: Structured metrics suitable for tooling and dashboards.
  • In-VM execution: capsem-bench runs inside the VM, with results saved to /tmp/capsem-benchmark.json.
  • Use Case: When you need to validate new changes, compare performance over time, or investigate slow operations.

Quick Start

Run the full benchmark suite inside the VM by executing just bench and inspect the JSON report at /tmp/capsem-benchmark.json.

Frequently Asked Questions about dev-benchmark

High-intent search queries and answers about installing and using this skill.

FAQPage Schema
How do I benchmark VM performance metrics for disk, startup, and http throughput?

VM performance benchmarking across disk, startup, and http is automated by running the full benchmark suite inside the VM. It executes all seven categories and outputs structured timing and throughput metrics to a JSON report.

What's the best way to detect performance regressions in Capsem components before release?

Detecting Capsem performance regressions involves running automated benchmarks inside the VM and comparing the JSON output over time. This validates optimizations and identifies slow operations before release.

Do I need capsem-bench installed inside the VM to run performance benchmarks?

Yes, capsem-bench must be available inside the VM to execute performance benchmarks. The tool runs in-VM and saves detailed timing and throughput results to /tmp/capsem-benchmark.json.

Can I run individual benchmark categories like snapshot or rootfs instead of the full suite?

Yes, individual benchmark categories including disk, rootfs, startup, http, throughput, and snapshot can be run independently. You can also select 'all' to execute the complete benchmark suite.

How does in-VM benchmarking output structured metrics for tooling and dashboards?

In-VM benchmarking outputs structured metrics by generating a JSON report at /tmp/capsem-benchmark.json. This file details timing and throughput data suitable for automated tooling and performance dashboards.

Why are my Capsem benchmark results showing slow operations after recent changes?

Slow operations after recent changes can be investigated by running benchmarks to compare current performance against previous JSON reports. This helps isolate whether new changes introduced performance regressions.