llamacpp-bench

name	llamacpp-bench
description	Run llama.cpp benchmarks on GGUF models to measure prompt processing (pp) and token generation (tg) performance. Use when the user wants to benchmark LLM models, compare model performance, test inference speed, or run llama-bench on GGUF files. Supports Vulkan, CUDA, ROCm, and CPU backends.

llamacpp-bench

Run standardized benchmarks on GGUF models using llama.cpp's llama-bench tool.

Quick Start

# Basic benchmark
llama-bench -m model.gguf -p 512,1024,2048 -n 128,256 -ngl 99

# With specific backend
LLAMA_BACKEND=vulkan llama-bench -m model.gguf -p 512,1024,2048 -n 128,256 -ngl 99

Benchmark Parameters

Parameter	Description	Default
-m	Model path (GGUF file)	required
-p	Prompt sizes to test	512
-n	Generation lengths to test	128
-ngl	GPU layers to offload	99
-t	CPU threads	auto
-dev	Device selection	auto

Standard Test Suite

For consistent comparisons across models, use:

-p 512,1024,2048 -n 128,256 -ngl 99

This tests:

• Prompt processing: 512, 1024, 2048 tokens
• Token generation: 128, 256 tokens

Interpreting Results

Metric	Meaning	Good Performance
pp512	Prompt processing speed at 512 tokens	>1000 t/s
pp1024	Prompt processing speed at 1024 tokens	>1000 t/s
pp2048	Prompt processing speed at 2048 tokens	>1000 t/s
tg128	Token generation speed (128 tokens)	>50 t/s
tg256	Token generation speed (256 tokens)	>50 t/s

Backend Selection

llama-bench auto-detects available backends. Priority order:

1. CUDA (NVIDIA GPUs)
2. ROCm (AMD GPUs)
3. Vulkan (cross-platform GPU)
4. CPU (fallback)

To force a backend, set environment variable or check build:

# Check available backends
llama-bench --help | grep -i "backend\|cuda\|rocm\|vulkan"

Batch Benchmarking

Use the provided script for benchmarking multiple models:

./scripts/benchmark_models.sh /path/to/models/*.gguf

Saving Results

Output can be redirected to a file:

llama-bench -m model.gguf -p 512,1024,2048 -n 128,256 -ngl 99 > results.txt

Or use the benchmark script which auto-saves to timestamped files.

Common Issues

1. Out of memory: Reduce -ngl (GPU layers) or test smaller prompt sizes
2. Slow CPU performance: Ensure -t matches CPU core count
3. Backend not found: Check llama.cpp was built with the desired backend

Building / Updating llama.cpp

Check Current Version

./scripts/build_llamacpp.sh -v

Shows:

• Current Git commit and branch
• Build date
• Whether behind upstream
• Available backends

Build or Update

# Interactive mode (prompts for backend selection)
./scripts/build_llamacpp.sh -u

# Specify backend directly
./scripts/build_llamacpp.sh -u -b vulkan   # Vulkan (AMD/Intel GPUs)
./scripts/build_llamacpp.sh -u -b cuda     # CUDA (NVIDIA GPUs)
./scripts/build_llamacpp.sh -u -b rocm     # ROCm (AMD GPUs)
./scripts/build_llamacpp.sh -u -b cpu      # CPU only

# Clean rebuild
./scripts/build_llamacpp.sh -c -b vulkan

# Custom build directory
./scripts/build_llamacpp.sh -u -b cuda -d /custom/path

Build Options

Flag	Description
-v	Show version info and exit
-u	Update to latest from GitHub
-c	Clean build (remove existing)
-b	Backend: vulkan, cuda, rocm, cpu
-d	Build directory path
-j	Parallel jobs (default: CPU count)

Finding llama-bench

The benchmark script auto-detects llama-bench in these locations:

• /DATA/Benchmark/llama.cpp/build/bin/llama-bench
• ~/Repo/llama.cpp/build/bin/llama-bench
• ~/lab/build/bin/llama-bench

If not found, it will search your home directory or you can build it using the script above.