Files
Easytier/easytier/benches/README.md
fanyang f24735a86f perf: reduce packet buffer slicing churn (#2381)
* bench: add packet bytes extraction Criterion benchmark

Adds a Criterion benchmark under easytier/benches/ covering
ZCPacket::payload_bytes and tunnel_payload_bytes at 1280/4096-byte payload
sizes, using iter_batched so ZCPacket construction stays in the setup phase
and is excluded from the timed region.

- Register the [[bench]] entry in easytier/Cargo.toml.
- Document the bench and PACKET_BYTES_* env vars in benches/README.md.

* perf: reduce packet buffer slicing churn

Replace BytesMut::split_off with Buf::advance in ZCPacket bytes
extraction paths (payload_bytes, tunnel_payload_bytes, convert_type,
drop_foreign_header) and in TunZCPacketToBytes, and simplify the
copy_from_slice in new_from_payload.

When the buffer is in its unique (VEC) representation, split_off promotes
it to the shared (ARC) representation, allocating a Shared control block
and bumping the refcount on every call, and pins the buffer in shared
mode. advance only mutates the in-place ptr/len/cap fields, avoiding that
allocation/refcount churn on the TX hot path. The byte data itself is not
copied by either path.
2026-07-01 23:19:34 +08:00

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7.1 KiB
Markdown

# Benchmarks
Criterion benchmarks for EasyTier hot paths.
| Bench | What it measures |
| --------------------------- | -------------------------------------------------------------------------------- |
| `tx_throughput` | End-to-end TX injection path through `peer_manager::send_msg_by_ip` |
| `packet_bytes_extraction` | `ZCPacket::payload_bytes` / `tunnel_payload_bytes` extraction (advance hot path) |
## Packet Bytes Extraction
Criterion benchmark for `ZCPacket` bytes extraction — the methods touched by the
`advance`-based slicing refactor. Measures `payload_bytes` and
`tunnel_payload_bytes` at two payload sizes (1280, 4096). Setup
(`ZCPacket::new_with_payload`) runs in the benchmark harness's preparation
phase and is excluded from the timed region, so the numbers reflect only the
extraction call.
### Quick start
```bash
cargo bench --bench packet_bytes_extraction
```
Smoke run:
```bash
PACKET_BYTES_MEASUREMENT_SECS=2 \
PACKET_BYTES_WARMUP_SECS=1 \
PACKET_BYTES_SAMPLE_SIZE=10 \
cargo bench --bench packet_bytes_extraction -- --quiet
```
### Environment variables
| Variable | Default | Notes |
| ------------------------------- | ------- | ---------------------------- |
| `PACKET_BYTES_MEASUREMENT_SECS` | `10` | Criterion `measurement_time` |
| `PACKET_BYTES_WARMUP_SECS` | `3` | Criterion `warm_up_time` |
| `PACKET_BYTES_SAMPLE_SIZE` | `10` | Criterion `sample_size` (min 10) |
---
## TX Throughput Benchmark
Criterion benchmark for EasyTier's TX injection path (`peer_manager::send_msg_by_ip`).
## What it measures
The benchmark sets up two EasyTier instances (`hot-a` / `hot-b`) and drives
packets from `hot-a` to `hot-b` via `peer_manager.send_msg_by_ip`. This is the
same entry point `easytier-core` uses for daily forwarded traffic, so the
numbers reflect the real TX hot path: NIC pipeline → route lookup →
compress/encrypt → peer connection → tunnel send.
Two variants are reported per tunnel kind:
| Bench | What it measures |
| --------------------------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| `tx_throughput/<tunnel>` | Serial baseline. One send in flight at a time. Reports per-packet CPU cost (TX injection latency). |
| `tx_throughput/<tunnel>-saturate` | Spawns `TX_THROUGHPUT_INFLIGHT` tokio tasks that independently pump `send_msg_by_ip`. Reports the aggregate throughput ceiling the peer manager + tunnel can sustain across worker threads. |
> **Out of scope (by design):** TUN read/write (`no_tun = true`), compression
> (default `None`), reverse/RX-side measurement, multi-peer fanout. Add
> separate benchmarks if you need those.
## Quick start
### ring tunnel (no root, fastest)
```bash
cargo bench --bench tx_throughput
```
Smoke run (faster iteration):
```bash
TX_THROUGHPUT_MEASUREMENT_SECS=2 \
TX_THROUGHPUT_WARMUP_SECS=1 \
TX_THROUGHPUT_SAMPLE_SIZE=10 \
cargo bench --bench tx_throughput -- --quiet
```
### tcp / udp tunnels (requires Docker + root)
The benchmark creates a Docker network and registers each container's netns
under `/var/run/netns`, which requires root. Run the whole command under
`sudo`:
```bash
sudo TX_THROUGHPUT_TUNNEL=tcp \
TX_THROUGHPUT_MEASUREMENT_SECS=5 \
TX_THROUGHPUT_WARMUP_SECS=2 \
TX_THROUGHPUT_INFLIGHT=64 \
cargo bench --bench tx_throughput -- --quiet
sudo TX_THROUGHPUT_TUNNEL=udp cargo bench --bench tx_throughput -- --quiet
```
> If `sudo` cannot find `cargo`, use `sudo -E` or the absolute path
> (`$(which cargo)`).
## Environment variables
| Variable | Default | Notes |
| -------------------------------- | --------------------- | -------------------------------------- |
| `TX_THROUGHPUT_TUNNEL` | `ring` | `ring` / `tcp` / `udp` |
| `TX_THROUGHPUT_PKT_SIZE` | `1400` | IP total length in bytes |
| `TX_THROUGHPUT_WORKER_THREADS` | `4` | tokio worker threads |
| `TX_THROUGHPUT_INFLIGHT` | `64` | saturate-mode concurrency (task count) |
| `TX_THROUGHPUT_TUNNEL_PORT` | `35521` | tcp/udp listen port |
| `TX_THROUGHPUT_MEASUREMENT_SECS` | `10` | Criterion `measurement_time` |
| `TX_THROUGHPUT_WARMUP_SECS` | `3` | Criterion `warm_up_time` |
| `TX_THROUGHPUT_SAMPLE_SIZE` | `10` | Criterion `sample_size` (min 10) |
| `TX_THROUGHPUT_DOCKER_IMAGE` | `busybox:latest` | tcp/udp only |
| `TX_THROUGHPUT_DOCKER_NET` | `easytier-bench-<id>` | auto-generated unique name |
| `TX_THROUGHPUT_DOCKER_SUBNET` | `172.31.250.0/24` | |
| `TX_THROUGHPUT_DOCKER_IP_A` | `172.31.250.2` | |
| `TX_THROUGHPUT_DOCKER_IP_B` | `172.31.250.3` | |
## Parameter sweeps
```bash
# Packet size
for sz in 64 256 1400 9000; do
TX_THROUGHPUT_PKT_SIZE=$sz cargo bench --bench tx_throughput -- --quick
done
# Inflight depth (self-check: depth=1 should match serial baseline)
for d in 1 4 16 64 256; do
TX_THROUGHPUT_INFLIGHT=$d cargo bench --bench tx_throughput -- --quick
done
# Worker threads
for w in 1 2 4 8; do
TX_THROUGHPUT_WORKER_THREADS=$w cargo bench --bench tx_throughput -- --quick
done
```
## Interpreting results
- **`<tunnel>`** reports per-packet latency. Lower is better. Throughput
column here is "what one in-flight sender sustains".
- **`<tunnel>-saturate`** reports aggregate throughput across
`TX_THROUGHPUT_INFLIGHT` concurrent senders. If this matches the serial
baseline, the TX path is bottlenecked on an internal serialization point
(lock, single-threaded queue, etc.) rather than CPU or link bandwidth.
### Known finding (ring, single peer)
On the ring tunnel with a single destination peer, saturate does **not** beat
serial (observed ~277 MiB/s saturate vs ~288 MiB/s serial on a 4-worker
runtime). This points to a serialization point inside the peer-connection TX
path. Tunnels with real I/O await points (tcp/udp via Docker) are expected to
show a saturate > serial gap; verify with the sudo commands above.
## Output artifacts
Criterion writes HTML reports + SVG plots under
`easytier/target/criterion/`. Open `tx_throughput/<tunnel>/report/index.html`
or `.../<tunnel>-saturate/report/index.html` in a browser to inspect
distributions and regressions across runs.