Performance Comparison of Compilers for C and C : Intel vs GCC GNU Compiler Collection

Introduction to Compiler Performance in C and C

When developing code in C or C for performance-critical applications, the choice of compiler can significantly impact the outcome. Two of the most commonly used compiler families are the GCC GNU Compiler Collection (GCC) and Intel's C compiler. This article explores the nuances of their performance differences, highlighting specific benchmark tests, factors affecting performance, and the trade-offs involved.

Overview of GCC Compiler Collection

The GCC GNU Compiler Collection (GCC) is an open-source, Unix-like compiler that supports multiple programming languages, including C and C . It is highly configurable and supports various operating systems and architectures. GCC's strength lies in its comprehensive toolchain and wide range of optimization features. However, its performance can vary based on the specific compiler version and compilation options chosen.

Intel C Compiler

Intel's C compiler is a proprietary tool designed for advanced performance tuning. It leverages Intel's hardware and microarchitecture knowledge to deliver superior performance. The Intel C Compiler is particularly strong in vectorization, parallelization, and optimization techniques that can significantly enhance code performance. Intel regularly releases updates and patches to optimize the compiler for the latest hardware and operating systems.

Factors Affecting Compiler Performance

Multiple factors influence the performance of a compiler, making it challenging to generalize the outcome between different compilers:

Code Type: The performance of a compiler can depend on the nature of the code. For example, some types of code may benefit more from GCC's optimizations, while others might see better results with Intel's compiler. Compiler Version: Different versions of a compiler can have varying optimization capabilities, which can greatly impact performance. It is essential to check the specific version's release notes for performance enhancements and bug fixes. Compilation Options: The choice of compilation options can significantly affect the performance outcomes. For instance, using the -O3 flag (GCC) or /QxHost (Intel) enables the compiler to apply aggressive optimizations, which can improve performance but also increase compile times. Trade-offs: Users must consider trade-offs between compilation speed and execution speed, memory footprint, and other factors when selecting a compiler. Some developers may prioritize faster compilation, while others might prioritize runtime performance.

Specific Benchmark Test Results

Various benchmark tests have been conducted to compare the performance of Intel's C compiler against GCC. Some notable results include:

Performance Benchmark Test 1: In a commonly cited benchmark, Intel's compiler showed a significant improvement in performance compared to GCC. This test targeted a highly optimized weather simulation application, where Intel's compiler achieved a 20% performance boost over GCC.

Performance Benchmark Test 2: Another benchmark focused on a parallel random-access machine (PRAM) application, which is a common test scenario for parallel computing. Intel's compiler outperformed GCC by 15%, demonstrating its strength in parallelization and vectorization. This result was attributed to Intel's use of advanced vector extensions and optimized instruction scheduling.

Performance Benchmark Test 3: A third benchmark tested a complex graphics rendering application. While GCC showed comparable performance, Intel's compiler achieved a 10% performance gain, primarily due to better loop unrolling and vectorization capabilities.

It is important to note that the results of these benchmark tests can vary based on the specific version of the compiler and the compilation options used. These tests are also subject to updates as compilers evolve to optimize for newer hardware and operating systems.

Conclusion

Choosing the right compiler for C or C development in performance-critical applications is crucial. While both GCC and Intel's C compiler are powerful tools, their performance can vary depending on the specific application, compiler version, and compilation options. Intel's compiler often shows better performance results in specific benchmarks, particularly in vectorization and parallelization. However, developers should carefully evaluate the trade-offs and select the compiler that best fits their project requirements.

For developers looking to optimize their code, it is recommended to:

Test both compilers with different versions and compilation options. Consider the specific performance requirements of their application. Evaluate factors such as compilation speed, memory footprint, and execution performance.

By understanding the nuances of compiler performance, developers can make informed decisions that lead to more efficient and high-performing applications.