json1.8 KB

Speedscope — Evented Profile with Open and Close Events (json)

The evented half of the speedscope format — explicit O and C events that must nest like brackets, rather than sampled stacks. Tracing profilers emit this shape, and an unbalanced or out-of-order close is the corruption a loader has to detect.

Observability JSON parsing Performance testing

Preview — first 50 linesjson

{
  "$schema": "https://www.speedscope.app/file-format-schema.json",
  "name": "checkout-api evented profile",
  "exporter": "novus-examples observability fixture",
  "activeProfileIndex": 0,
  "shared": {
    "frames": [
      {
        "name": "(root)"
      },
      {
        "name": "main"
      },
      {
        "name": "http.(*conn).serve"
      },
      {
        "name": "checkout.Handle"
      },
      {
        "name": "checkout.price"
      },
      {
        "name": "pricing.applyDiscount"
      },
      {
        "name": "encoding/json.Marshal"
      },
      {
        "name": "sql.(*DB).QueryContext"
      },
      {
        "name": "runtime.gcBgMarkWorker"
      }
    ]
  },
  "profiles": [
    {
      "type": "evented",
      "name": "cpu",
      "unit": "nanoseconds",
      "startValue": 0,
      "endValue": 8000000000,
      "events": [
        {
          "type": "O",
          "frame": 1,
          "at": 0
        },
        {

… 99 lines total — download for the full file.

Specifications

Profile Type: evented
Events: 10
Open Events: 5
Close Events: 5
Properly Nested: true
Unit: nanoseconds
End Value: 8000000000

Testing contract

Expected to pass

Scenario: Replay the event stream and maintain a call stack.
Expected result: The ten events open and close in strict LIFO order leaving an empty stack at endValue, and every close event matches the frame at the top of the stack.

What is a .json file?

JSON (JavaScript Object Notation) is a lightweight, text-based data-interchange format representing objects, arrays, strings, numbers, booleans, and null. It is language-independent, human-readable, and the dominant format for web APIs and configuration. It requires a single well-formed root value.

How to use this file

Use an example JSON file to test parsers and serializers, schema validation, Unicode and number-precision handling, and API request or response processing.

How to use this file for testing

“Speedscope — Evented Profile with Open and Close Events (json)” is a deterministic Novus Examples fixture for Observability, JSON parsing, Performance testing. Structured and plain-text telemetry with known timestamps, levels, request identifiers, and error states for testing log ingestion, correlation, dashboards, and alert pipelines.

Documented properties for this file: JSON · 1,803 bytes. Compare results against paired or grouped companions on this page when present (clean↔damaged, searchable↔scanned, or format twins) so scores stay reproducible across runs.

Download the file once, keep the path stable in CI or local scripts, and treat the spec table as the contract: dimensions, seeds, field lists, and roles are intentional. Corrupt or invalid samples are labelled as such — expect parsers to fail loudly rather than silently accept them.

Telemetry fixtures use fixed trace IDs, span IDs, and timestamps so ingestion is reproducible run to run. Point your collector, parser, or query layer at the file and assert the documented span tree, metric families, or severity mix; service and host names are invented.

Code examples

import json

with open("speedscope-evented-profile.json") as f:
    data = json.load(f)
print(type(data), len(data))

Generated by generation/observability.py. Free for any use, no attribution required — license.