# quasi-bench

What a described screen costs to render, in time and in allocations.

```
cargo run --release -p quasi-bench                    # nanoseconds per render
cargo run --release -p quasi-bench --features count   # allocations per render
```

Two builds, because the counting allocator is real instrumentation and a timing
number taken through it is a number about the instrumentation.

Read the allocation count first. It is stable across machines and across
whatever else the box is doing; the timing is a sanity check beside it, and on a
shared dev box a 10% difference in it is noise.

Read down the row-count column rather than across renderers. A cost flat across
5, 25 and 200 rows is fixed and a cost that tracks them is per-row. Comparing
the webview's number to the terminal's compares a string builder to a cell
painter, and the two columns do not mean the same thing: the webview emits every
row, the terminal draws one 160x50 frame and the rest is scroll state.

`quasi-immediate` is absent. Its entry point needs a live egui `Ui`, so
measuring it means standing up an egui harness rather than calling a function.

## Baseline, fw13

The screen is a copy of MNW's `library_contacts` pane: two tables, five columns
and two, linked values in two flavours, a destructive per-row act.

Allocations per render (allocs / bytes):

| rows | webview fragment | webview screen | terminal |
|------|------------------|----------------|----------|
| 5 | 205 / 37,890 | 207 / 38,734 | 2,375 / 357,997 |
| 25 | 807 / 146,984 | 809 / 147,828 | 3,988 / 506,255 |
| 200 | 6,060 / 1,130,426 | 6,062 / 1,131,270 | 12,576 / 1,230,646 |

Nanoseconds per render, best of 5 passes of 20,000:

| rows | webview fragment | webview screen | terminal |
|------|------------------|----------------|----------|
| 5 | 6,171 | 6,693 | 299,376 |
| 25 | 28,026 | 30,225 | 401,624 |
| 200 | 204,136 | 206,474 | 497,650 |

Two things worth knowing before reading these as a verdict on anything.

The shell is nearly free. A whole screen costs two allocations more than the
fragment inside it, at every size, so the head and the stylesheet links are not
where a page load goes.

The terminal is the expensive column and its cost is mostly not per-row. 2,375
allocations to draw a five-row screen against the webview's 205, rising only to
12,576 at 200 rows where the webview reaches 6,060. Sublinear because the frame
clips.