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diff --git a/docs/tutorial/tutorial.md b/docs/tutorial/tutorial.md new file mode 100644 index 0000000..a3695de --- /dev/null +++ b/docs/tutorial/tutorial.md @@ -0,0 +1,245 @@ +# I/O Riot NG: a guided tour + +This tutorial walks through every major surface of `ior` — the dashboard tabs, the live stream, recording, headless modes, and the in-TUI flamegraph — using short animated GIFs so you can *see* what the keys actually do. + +Every GIF in this document is regenerated from a [VHS](https://github.com/charmbracelet/vhs) tape under [`tapes/`](./tapes). To rebuild them all, run `sudo -v && mage demo` (see [Regenerating the demo](#regenerating-the-demo)). + +## Contents + +1. [Installing ior](#installing-ior) +2. [First launch: the PID picker](#first-launch-the-pid-picker) +3. [Touring the dashboard tabs](#touring-the-dashboard-tabs) + - [1 · Flamegraph (default landing tab)](#1--flamegraph-default-landing-tab) + - [2 · Overview](#2--overview) + - [3 · Syscalls](#3--syscalls) + - [4 · Files](#4--files) + - [5 · Processes](#5--processes) + - [6 · Latency + Gaps](#6--latency--gaps) + - [7 · Stream](#7--stream) +4. [Mastering the Stream tab](#mastering-the-stream-tab) + - [Pause + stacked filters](#pause--stacked-filters) + - [Regex search](#regex-search) + - [CSV export](#csv-export) +5. [Choosing what to trace](#choosing-what-to-trace) +6. [Recording for offline analysis](#recording-for-offline-analysis) + - [TUI Parquet recording](#tui-parquet-recording) + - [Headless modes](#headless-modes) +7. [Regenerating the demo](#regenerating-the-demo) + +## Installing ior + +See the [main README](../../README.md) for full install steps. The quickest path from any Docker-capable Linux host: + +```shell +git clone https://codeberg.org/snonux/ior ~/git/ior +cd ~/git/ior +mage buildDocker # builds inside a Rocky 9 container, ~15 min on first run +``` + +For a native build (libbpfgo must be cloned alongside the repo first — see the README): + +```shell +mage all +``` + +ior needs `CAP_BPF`, so every invocation below uses `sudo`. + +The build dance only has to happen once: the resulting `ior` binary is fully statically linked and uses CO-RE, so the same binary runs on any BTF-enabled Linux kernel without recompilation. See the [Compile once, run everywhere](../../README.md#compile-once-run-everywhere) section for details. + +## First launch: the PID picker + +`sudo ./ior` starts with the **PID picker**. The cursor is on **All PIDs**, so pressing `Enter` traces the whole system. Type into the filter box to narrow the list by PID, comm, or cmdline; arrow keys move the selection. + + + +The same picker can be re-opened later from the dashboard with `p`. + + + +## Touring the dashboard tabs + +The dashboard has seven tabs, addressable by number key. The default landing tab is **Flamegraph**. `tab` / `shift+tab` step forward / back. + +| Key | Tab | What it shows | +|-----|-------------------|--------------------------------------------------------------------------| +| `1` | Flamegraph (`Flm`)| Live FlameGraph of the configured stack (`comm`/`path`/`tracepoint`) | +| `2` | Overview (`Ovr`) | Sparkline + top syscalls + top paths summary | +| `3` | Syscalls (`Sys`) | Sortable per-syscall counters, latency, byte volume | +| `4` | Files (`Fil`) | Per-path counters; `d` toggles directory grouping | +| `5` | Processes (`Pro`) | Per-process / per-comm counters | +| `6` | Latency (`Lat`) | Latency + inter-syscall gap histograms | +| `7` | Stream (`Str`) | Live tail of individual traced events | + +### 1 · Flamegraph (default landing tab) + +The first thing you see after dismissing the PID picker is the **live flamegraph**. Bars grow as new events come in. `o` cycles the stack ordering (e.g. `comm/path/tracepoint` ↔ `comm/tracepoint/path`); `b` toggles the size metric (event count vs. bytes). + + + +### 2 · Overview + +Press `2`. The Overview tab is the at-a-glance view: a sparkline of recent event volume, the top syscalls, and the top paths. + + + +### 3 · Syscalls + +Press `3`. A sortable table of every traced syscall (count, average latency, total bytes). `j` / `k` (or arrow keys) scroll the rows; `←` / `→` move the selected column; `s` sorts by the selected column using its default direction; `S` reverses. + + + +### 4 · Files + +Press `4`. Per-path counters. The most useful key here is `d`, which toggles **directory grouping** — paths roll up into their parent directory, which is essential when one process touches thousands of files in `/usr/share/...`. + + + +### 5 · Processes + +Press `5`. Per-process / per-comm view. `S` reverse-sorts; combine with `←` / `→` to pick a column. + + + +### 6 · Latency + Gaps + +Press `6`. Two histograms: syscall **latency** (how long the syscall ran) and the inter-syscall **gap** (idle time on the same thread between syscalls). The big-write workload running in the background spreads the latency distribution noticeably. + + + +### 7 · Stream + +Press `7`. A live tail of every traced event row — comm, PID, TID, syscall, file, FD, return value, bytes, latency, gap. This is the workhorse view; the next section explores it in depth. + + + +## Mastering the Stream tab + +Stream has two modes: **Live** (rows scroll past) and **Pause** (`space` toggles). Almost everything interesting happens in pause mode. + +### Pause + stacked filters + +In pause mode, navigate with `j`/`k` (rows) and `←` / `→` (columns). Pressing `Enter` on the selected cell **pushes a new filter onto a stack** and immediately re-filters the ring buffer. Filters are stackable, so you can drill down — first by `Comm`, then by `Syscall`, then by `File`. `Esc` pops the most recent filter (LIFO); keep hitting `Esc` to undo all the way back. + + + +The filter is reflected in the bottom status line, and matches the same syntax you'd type by hand: `comm~bash`, `syscall~openat`, `latency>=100000`, etc. + +### Regex search + +`/` opens a forward regex prompt; `?` opens a backward one. `n` jumps to the next match in the same direction; `N` reverses. The search runs against every column on every row in the ring buffer and wraps at the end. + + + +### CSV export + +Four keys, four flavours: + +- `e` — quick export of the **current TUI-filter snapshot** to `ior-stream-<timestamp>.csv` in the current working directory. Works from any tab, not just Stream. +- `x` — quick export of the **paused stream view** specifically (preserves your filter stack). +- `X` — same as `x`, but prompts for a filename first. +- `E` — open the most recent stream-exported CSV in your `$EDITOR` (`hx` / `vi` fallback). + + + +If you don't want CSV export at all, start ior with `-tuiExport=false`; the help footer hides the export keys and `e` becomes a no-op. + +## Choosing what to trace + +Three modal pickers reshape what the rest of the TUI sees: + +- `p` — **PID picker** (re-opens the launch picker). +- `t` — **TID picker** for thread-level focus. +- `o` — **Probes** dialog: enable / disable individual syscall tracepoints. + + + +Restricting to a single PID is also exposed as a CLI flag (`-pid <n>`), as is comm/path filtering (`-comm`, `-path`). Tracepoint subsetting on the command line uses `-tps <regex>` / `-tpsExclude <regex>`. + +## Recording for offline analysis + +ior has three persistence flows; each solves a different problem. + +| Flow | How | What you get | +|------------------------|----------------------------------------------|---------------------------------------------------------| +| TUI Parquet recording | `R` from the dashboard | streaming Parquet of every row that passes your filter | +| Headless `.ior.zst` | `sudo ./ior -flamegraph -name <name>` | one aggregated native trace artifact (bandwidth-cheap) | +| Headless Parquet | `sudo ./ior -parquet trace.parquet` | streaming Parquet, full firehose, no TUI | +| Plain CSV | `sudo ./ior -plain` | one CSV row per event on stdout | + +### TUI Parquet recording + +Press `R` in the dashboard, accept the default filename (`ior-recording-<timestamp>.parquet`) with `Enter`, and rows start streaming to disk. The footer shows the active recording path (or the last error). Press `R` again to stop. + + + +The recorder follows your *current* TUI global filter — narrow with `p`/`t`/`o` first if you want a focused capture. + +### Headless modes + +For unattended captures or scripting, skip the TUI entirely. The demo runs all three back-to-back, capped with `-duration` so each terminates on its own. + + + +`-flamegraph` writes one aggregated `.ior.zst` artifact at shutdown — ideal for `ior`'s native flamegraph and integration workflows. `-parquet` streams every row, so the file grows continuously. `-plain` is the lightest weight: CSV to stdout you can pipe into anything. + +## Regenerating the demo + +The whole asset pipeline is reproducible: + +```shell +mage installDemoTools # one-time: VHS via go install + ttyd via dnf +sudo -v # warm the sudo timestamp once +mage demo # regen all 14 GIFs + screenshots (~10 min) +``` + +Or rebuild a single tape after editing it: + +```shell +TAPE=07-stream-live mage demoOne +``` + +Tapes live in [`tapes/`](./tapes), the background workload that drives them is [`scripts/workload.sh`](./scripts/workload.sh), and the resulting assets land in [`assets/`](./assets). VHS records headlessly under `ttyd` + Chromium — no real terminal window opens, so `mage demo` is safe to run in the background while you keep working. + +## Hotkey Quick Reference + +### Global keys + +| Key | Action | +|-----|--------| +| `tab` / `shift+tab` | next / previous tab | +| `1`–`7` | jump to tab by number (1=Flame, 2=Overview, 3=Syscalls, 4=Files, 5=Processes, 6=Latency, 7=Stream) | +| `H` | toggle bottom help panel | +| `e` | export filtered stream snapshot to CSV | +| `R` | start / stop Parquet recording | +| `p` | re-open PID picker | +| `t` | open TID picker | +| `o` | open probe selection dialog | +| `r` | refresh dashboard snapshot | +| `q` / `ctrl+c` | quit | + +### Tab-specific keys (`3:Syscalls`, `4:Files`, `5:Processes`) + +| Key | Action | +|-----|--------| +| `s` | sort by selected column (default direction) | +| `S` | reverse-sort by selected column | +| `j`/`k` or `↑`/`↓` | scroll list | +| `d` (Files only) | toggle directory grouping | + +### Stream tab (`7:Stream`) + +| Key | Action | +|-----|--------| +| `space` | toggle live / pause mode | +| `g` / `G` | jump to top / tail | +| `j`/`k` or `↑`/`↓` | move row (pause) / scroll (live) | +| `←`/`→` or `h`/`l` | move selected column (pause only) | +| `enter` | push cell value as filter (pause) | +| `esc` | pop most recent filter (LIFO) | +| `c` | clear all stream filters | +| `f` | open advanced filter modal | +| `/` / `?` | regex search forward / backward | +| `n` / `N` | next / previous search match | +| `x` | quick CSV export of paused view | +| `X` | CSV export with filename prompt | +| `E` | open last CSV export in `$EDITOR` | |