apm-php-bench

Benchmark four PHP runtime/instrumentation variants under the same load profile and compare their telemetry and response time behavior.

What this repo does

This stack runs:

• A Slim PHP app in 4 variants:
  • uninstrumented (uninstrumented)
  • apm-php-9-alpha (solarwinds/apm + solarwinds/apm_ext + swotel collector)
  • otel (OpenTelemetry PHP auto-instrumentation)
  • apm-8 (Current GA Solarwinds APM PHP library)
• A Locust load generator that continuously hits all 4 variants.
• Three collectors:
  • otel-collector-locust for Locust OTLP metrics export
  • otel-collector-apm-php-9-alpha for solarwinds/apm telemetry export
  • otel-collector-otel for OpenTelemetry PHP telemetry export

The default benchmark target route is /complex, which intentionally creates spans and emits app-side metrics/logs to stress instrumentation overhead.

Architecture

Component	Service name	Purpose	Host port
Slim baseline	nginx-uninstrumented -> php-fpm-uninstrumented	No APM instrumentation	8000
Slim + apm-php-9-alpha	nginx-apm-php-9-alpha -> php-fpm-apm-php-9-alpha	solarwinds/apm + solarwinds/apm_ext + swotel collector	8001
Slim + otel	nginx-otel -> php-fpm-otel	OpenTelemetry PHP auto-instrumentation exporting OTLP telemetry	8002
Slim + apm-8	nginx-apm-8 -> php-fpm-apm-8	Current GA Solarwinds APM PHP library	8003
Load generator	apm-php-bench-locust	Headless Locust workload + custom OTLP metric	n/a
Collector (Locust)	otel-collector-locust	Forwards telemetry from Locust to backend	n/a
Collector (alpha)	otel-collector-apm-php-9-alpha	Forwards telemetry from APM PHP alpha to backend	n/a
Collector (otel)	otel-collector-otel	Forwards telemetry from OpenTelemetry PHP app to backend	n/a

Prerequisites

• Docker Desktop (or Docker Engine + Compose plugin)
• Valid collector/token values for your backend

Configuration

A template exists at .env.dev:

OTEL_COLLECTOR=<otel-collector>
OTEL_TOKEN=<token>
SW_APM_COLLECTOR=<apm-collector>
SW_APM_TOKEN=<token>

Use either of these options:

1. Run Compose directly with the template file
2. Copy .env.dev to .env and edit values

cp .env.dev .env

Quick start

docker compose --env-file .env.dev up --build

If you use .env, you can omit --env-file:

docker compose up --build

Stop and clean up:

docker compose down

Sanity checks

After startup, verify health endpoints:

curl -fsS http://localhost:8000/healthcheck
curl -fsS http://localhost:8001/healthcheck
curl -fsS http://localhost:8002/healthcheck
curl -fsS http://localhost:8003/healthcheck

Expected response:

Yay healthy

Benchmark behavior

Locust starts in headless mode with:

• 8 users
• spawn rate 5
• host http://0.0.0.0:8000 (individual tasks call service DNS names directly)

Tasks in locust-app/locustfile.py call:

• http://nginx-uninstrumented/complex as uninstrumented
• http://nginx-apm-php-9-alpha/complex as 9.0.0-alpha
• http://nginx-otel/complex as otel
• http://nginx-apm-8/complex as 8.13.0

Locust also publishes a custom histogram metric:

• metric name: apm.php.benchmark.response.time
• attribute key: benchmark.app.kind

Slim app routes

Available routes in slim-app/index.php:

• /healthcheck - liveness check
• /request - outbound call to example.com
• /metrics - app counters + histogram, includes sleep(1) for stable response-time profile
• /logs - emits logs via Monolog OTel handler
• /sdk - manual SDK span + outbound call
• /complex - benchmark-heavy path (creates many manual spans and records metrics)

Project structure

.
├── docker-compose.yaml
├── otel-collector-config.yaml
├── swotel-collector-config.yaml
├── locust-app/
│   ├── Dockerfile
│   ├── locustfile.py
│   └── requirements.txt
└── slim-app/
    ├── Dockerfile-uninstrumented
    ├── Dockerfile-apm-php-9-alpha
    ├── Dockerfile-otel
    ├── Dockerfile-apm-8
    ├── composer-uninstrumented.json
    ├── composer-apm-php-9-alpha.json
    ├── composer-otel.json
    ├── index.php
    └── nginx-*.conf

Troubleshooting

• Containers exit early: inspect logs with docker compose logs --tail=200 <service>.
• Health check fails: ensure php-fpm-* services built successfully and Nginx depends_on conditions are met.
• No telemetry in backend: verify .env(.dev) token/collector values and collector service connectivity.

License

Licensed under Apache 2.0. See LICENSE.