Phuong Le

Go Runtime Metrics: CPU, GC, Memory, Scheduler

Sat, 30 May 2026 09:00:00 +0700

Go exposes many runtime metrics through runtime/metrics, and many metrics clients (Prometheus, VictoriaMetrics) use it to export Go runtime stats from your application. These metrics include things like:

how much memory your Go runtime has mapped,

how much is used by heap objects,

how much is free,

how much has been returned to the OS,

how much time goroutines have spent waiting for mutex locks,

etc.

Getting Go runtime stats in a few lines:

About

Sat, 30 May 2026 00:00:00 +0000

I’m Phuong Le (you’ll find me as @func25 most places). I’m a software engineer at VictoriaMetrics, working on VictoriaLogs — which means I spend my days deep in Go, performance, and storage internals.

I also write Devtrovert, where I try to explain backend engineering, system design, and the parts of Go that usually stay hidden — the runtime, the scheduler, defer, the memory model — in a way that’s practical rather than academic.

Sat, 30 May 2026 00:00:00 +0000

Practical Go, sent when there’s something worth saying. Runtime deep dives, performance notes, and patterns that survive contact with production.

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Sat, 30 May 2026 00:00:00 +0000

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Questions? Reach out on X / Twitter or GitHub.

SIGHUP Signal for Configuration Reloads

Wed, 23 Apr 2025 09:00:00 +0700

Many applications, including Go applications by default, respond to three signals for termination: SIGTERM, SIGINT, and SIGHUP. Among these, SIGHUP carries some extra nuances and may be less relevant today.

By definition:

SIGHUP (“signal hang up”) is a signal sent to a process when its controlling terminal is closed. – Wikipedia

But what exactly is a “controlling terminal”?

Terminal

Suppose you open a terminal application. This is the window where you see text and type commands. It might be iTerm2, Terminal.app on macOS, or GNOME Terminal on Linux. This window is a graphical interface, but inside it, another program is actually running your commands. That program is usually a shell like bash or zsh.

Goroutine Scheduler Revealed: Never See Goroutines the Same Way Again

Tue, 02 Jan 2024 09:00:00 +0700

Don’t worry about understanding the image above right now, as we’re going to begin with the very basics.

Goroutines are distributed into threads, which Goroutine Scheduler handle behind the scene. From our previous talks, we know a few things about goroutines:

Goroutines in terms of raw execution speed, aren’t necessarily faster than threads since they need an actual thread to run on.
The real advantage of goroutines lies in areas like context switching, memory footprint, the cost of creation and teardown.

You might have heard of the Goroutine Scheduler before, but how well do we really know how it works? How does it pair goroutines with threads?

Go Channels Explained: More than Just a Beginner’s Guide.

Fri, 29 Dec 2023 09:00:00 +0700

After discussing Goroutines, diving into Goroutines vs OS Threads, examining MAXPROCS in the previous post, Goroutines: Think You Know Go Basics? Think Again.

We are now ready to talk about Channels, which act as synchronization points.

1. Channel

Imagine a channel as a simple pipe, this pipe connects different goroutines, allowing them to talk to each other by sending data into one end of the pipe and receiving it from the other.

Select & For Range Channel in Go: Breaking Down

Tue, 26 Dec 2023 09:00:00 +0700

In our previous discussion, we covered five specific channel types in Go: buffered, unbuffered, directional, nil and closed channels.

If you missed that discussion, it’s important to note that we identified these types to provide a detailed understanding. Yet, at the most basic level, Go channels are primarily either buffered or unbuffered.

Now, we’re focusing on select and for range in Go.

1. Understanding select

Basically, the select statement provides a mechanism for a goroutine to wait on multiple channels using the case statement and its main job is to execute the first case that is ready.

Phuong Le

Go Runtime Metrics: CPU, GC, Memory, Scheduler

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SIGHUP Signal for Configuration Reloads

Terminal

Goroutine Scheduler Revealed: Never See Goroutines the Same Way Again

Go Channels Explained: More than Just a Beginner’s Guide.

1. Channel

Select & For Range Channel in Go: Breaking Down

1. Understanding select