# Volt Network Benchmarks

Comprehensive benchmark suite for comparing network backend performance in Volt VMs.

## Quick Start

```bash
# Install dependencies (run once on each test machine)
./setup.sh

# Run full benchmark suite
./run-all.sh <server-ip> <backend-name>

# Or run individual tests
./throughput.sh <server-ip> <backend-name>
./latency.sh <server-ip> <backend-name>
./pps.sh <server-ip> <backend-name>
```

## Test Architecture

```
┌─────────────────┐         ┌─────────────────┐
│  Client VM      │         │  Server VM      │
│  (runs tests)   │◄───────►│  (runs servers) │
│                 │         │                 │
│  ./throughput.sh│         │  iperf3 -s      │
│  ./latency.sh   │         │  sockperf sr    │
│  ./pps.sh       │         │  netserver      │
└─────────────────┘         └─────────────────┘
```

## Backends Tested

| Backend | Description | Expected Performance |
|---------|-------------|---------------------|
| `virtio` | Pure virtio-net (QEMU userspace) | Baseline |
| `vhost-net` | vhost-net kernel acceleration | ~2-3x throughput |
| `macvtap` | Direct host NIC passthrough | Near line-rate |

## Running Benchmarks

### Prerequisites

1. Two VMs with network connectivity
2. Root/sudo access on both
3. Firewall rules allowing test traffic

### Server Setup

On the server VM, start the test servers:

```bash
# iperf3 server (TCP/UDP throughput)
iperf3 -s -D

# sockperf server (latency)
sockperf sr --daemonize

# netperf server (PPS)
netserver
```

### Client Tests

```bash
# Test with virtio backend
./run-all.sh 192.168.1.100 virtio

# Test with vhost-net backend
./run-all.sh 192.168.1.100 vhost-net

# Test with macvtap backend
./run-all.sh 192.168.1.100 macvtap
```

### Comparison

After running tests with all backends:

```bash
./compare.sh results/
```

## Output

Results are saved to `results/<backend>/<timestamp>/`:

```
results/
├── virtio/
│   └── 2024-01-15_143022/
│       ├── throughput.json
│       ├── latency.txt
│       └── pps.txt
├── vhost-net/
│   └── ...
└── macvtap/
    └── ...
```

## Test Details

### Throughput Tests (`throughput.sh`)

| Test | Tool | Command | Metric |
|------|------|---------|--------|
| TCP Single | iperf3 | `-c <ip> -t 30` | Gbps |
| TCP Multi-8 | iperf3 | `-c <ip> -P 8 -t 30` | Gbps |
| UDP Max | iperf3 | `-c <ip> -u -b 0 -t 30` | Gbps, Loss% |

### Latency Tests (`latency.sh`)

| Test | Tool | Command | Metric |
|------|------|---------|--------|
| ICMP Ping | ping | `-c 1000 -i 0.01` | avg/p50/p95/p99 µs |
| TCP Latency | sockperf | `pp -i <ip> -t 30` | avg/p50/p95/p99 µs |

### PPS Tests (`pps.sh`)

| Test | Tool | Command | Metric |
|------|------|---------|--------|
| 64-byte UDP | iperf3 | `-u -l 64 -b 0` | packets/sec |
| TCP RR | netperf | `TCP_RR -l 30` | trans/sec |

## Interpreting Results

### What to Look For

1. **Throughput**: vhost-net should be 2-3x virtio, macvtap near line-rate
2. **Latency**: macvtap lowest, vhost-net middle, virtio highest
3. **PPS**: Best indicator of CPU overhead per packet

### Red Flags

- TCP throughput < 1 Gbps on 10G link → Check offloading
- Latency P99 > 10x P50 → Indicates jitter issues
- UDP loss > 1% → Buffer tuning needed

## Troubleshooting

### iperf3 connection refused
```bash
# Ensure server is running
ss -tlnp | grep 5201
```

### sockperf not found
```bash
# Rebuild with dependencies
./setup.sh
```

### Inconsistent results
```bash
# Disable CPU frequency scaling
echo performance | sudo tee /sys/devices/system/cpu/cpu*/cpufreq/scaling_governor
```