nim-chroprof/README.md

chroprof - Profiling for Chronos

This repo contains a usable profiler for Chronos. For the time being, it requires a modified version of Chronos (V3, V4) which has profiling hooks enabled.

1. Enabling profiling
2. Looking at metrics
3. Enabling profiling with Prometheus metrics
4. Limitations

Enabling Profiling

Profiling must be enabled per event loop thread. To enable it, you need to call, from the thread that will run your event loop:

import chroprof

enableProfiling()

Looking at Metrics

At any time during execution, you can get a snapshot of the profiler metrics by calling getMetrics(). This will return a MetricsTotals object which is a table mapping FutureTypes to AggregateMetrics. You may then print, log, or do whatever you like with those.

getMetrics() will return the metrics for the event loop that is running (or ran) on the calling thread.

Enabling profiling with Prometheus metrics

You can export metrics on the top-k async procs that are occupying the event loop thread the most by enabling the profiler's nim-metrics collector:

import chroprof/collector

# Exports metrics for the 50 heaviest procs
enableProfilerMetrics(50)

with the help of Grafana,