wolfssl-examples/staticmemory/memory-bucket-optimizer

Memory Bucket Optimizer for wolfSSL

This tool analyzes memory allocation patterns in wolfSSL and recommends optimal static memory bucket configurations to minimize wasted memory.

Overview

When wolfSSL is built with the --enable-staticmemory option, it uses a static memory management system with memory buckets. The size and distribution of these buckets can significantly impact memory usage efficiency. This tool helps optimize these bucket configurations for specific TLS operations.

Software Bill of Materials (SBOM)

Component	Description	License
Memory Bucket Optimizer	Core optimization tool	GPLv2
wolfSSL	TLS/SSL library	GPLv2
gnuplot	Plotting utility	GPLv2
Bash Scripts	Automation scripts	GPLv2
Example Applications	Demo applications	GPLv2

Directory Structure

memory-bucket-optimizer/
├── src/                    # Source code for the optimizer
├── results/                # Results of optimization runs
├── examples/               # Example applications using optimized buckets
├── visualization/          # Visualization scripts and plots
├── run_multiple.sh         # Script to run tests for multiple TLS operations
├── compare_memory.sh       # Script to compare memory usage
└── README.md               # This file

Prerequisites

• wolfSSL (built with --enable-memorylog and --enable-staticmemory)
• GCC compiler
• gnuplot (for visualization)

Building

make

Usage

Basic Usage

1. Build wolfSSL with memory logging enabled:

cd ~/repos/wolfssl
./configure --enable-memorylog --enable-staticmemory && make

2. Run the optimizer:

./run_multiple.sh

This will:

• Run the example client with different TLS operations
• Collect memory allocation logs
• Generate optimized bucket configurations for each operation
• Create visualization plots

Advanced Usage

To optimize for a specific TLS operation:

./src/memory_bucket_optimizer results/tls13_google_memory.txt > results/tls13_google_buckets.txt

To compare memory usage between default and optimized configurations:

./compare_memory.sh

Visualization

The visualization directory contains scripts to generate plots:

• Allocation size histograms
• Bucket optimization plots
• TLS operation comparisons

To generate plots:

cd visualization
./generate_data.sh

Example Applications

The examples directory contains example applications that demonstrate how to use the optimized bucket configurations in your wolfSSL applications.

Testing with WOLFSSL_NO_MALLOC

To ensure that the optimized bucket configurations work correctly without falling back to system malloc, you can use the test_with_no_malloc.sh script:

./test_with_no_malloc.sh ~/repos/wolfssl tls13_google

This script:

• Builds wolfSSL with CPPFLAGS=-DWOLFSSL_NO_MALLOC and --enable-staticmemory
• Creates a test application with the optimized bucket configuration
• Runs the test application to verify that it works correctly without system malloc
• Confirms that the memory bucket optimization is effective for embedded systems

This testing is critical for embedded systems where dynamic memory allocation is not available or not desired.

Algorithm

The memory bucket optimizer uses the following algorithm:

1. Parse memory allocation logs to identify allocation sizes and frequencies
2. Sort allocation sizes from smallest to largest
3. Select the most frequent allocation sizes as bucket sizes
4. Assign distribution values based on allocation frequency
5. Calculate memory waste and optimize for minimal overhead

License

This project is licensed under the GPL v2.0 License - see the LICENSE file for details.