How to Speed Up Python Code

Python has become the undisputed champion of data science. Its intuitive syntax, rich ecosystem of libraries, and active community offer a powerful environment for exploring data, building models, and extracting actionable insights. However, the larger your datasets and the more complex your algorithms, the more likely you are to encounter Python’s performance limitations. Delays during computations can slow down iteration and experimentation, both crucial aspects of the data science workflow.

If you’re wondering how to speed up Python code, there’s good news: you don’t have to abandon Python for the sake of speed. There are tools and techniques designed to achieve significant performance improvements within Python. This means you can continue to use the libraries you’re already familiar with, while also unlocking new levels of speed, scalability, and performance for your projects.

Core Python Optimization Techniques

To speed up Python code, focus first on core optimizations. Let’s explore some fundamental techniques that can streamline your Python data workflows.

Profiling: Finding the Bottlenecks

Before deep diving into optimization, it’s important to understand where your code is spending its time. Python offers some helpful profiling tools:

  • timeit: This module is great to quickly check the timing of small code snippets.
  • cProfile: This tool provides more detailed profiling reports about the time spent within different functions in your code.

For even more in-depth analysis, consider these powerful third-party profiling tools:

  • Scalene: Offers advanced memory profiling features, helping you identify memory leaks and inefficient memory usage.
  • py-spy: A low-overhead sampling profiler, capable of profiling running Python processes without significant slowdown.

By using profiling, you’ll avoid wasting efforts optimizing the wrong parts of the code.

Using Built-in Capabilities

Python’s standard library includes many functions and data structures that are optimized under the hood (and implemented in C). Using them wisely can result in significant performance gains:

  • Lists vs. Tuples: Tuples are immutable, making them slightly faster and more memory efficient in cases where you don’t need to modify the data after creation.
  • Sets and Dictionaries: These offer fast, constant-time lookups by key, making tasks like checking for membership or uniqueness much more efficient.

Despite the effectiveness of the mentioned optimization tips, the question of how to speed up Python code often involves exploring tools and practices that go beyond Python’s built-in capabilities.

Going Beyond Standard Python

When the fundamental optimizations aren’t enough, there are tools that bridge the gap between Python’s accessibility and native code performance. However, it’s important to be aware of the trade-offs these methods often involve before starting to use them.

Cython: C-like Speeds, C-like Complexity

Cython is a Python-like language that’s typically used to write Python extension modules. Cython compiles to C/C++ – giving substantial performance improvements over standard Python – and supports statically-enforced type annotations.  However, using Cython effectively comes with downsides:

  • Added Development Complexity: Cython introduces a significant shift away from pure Python. Understanding C data types, memory management, and how Python interacts with C code is necessary.
  • Maintenance Overhead: Your codebase would have both Python and Cython components, increasing the complexity of updates and debugging.
  • Limited Applicability: Not all Python code translates smoothly to Cython. Using libraries heavily relying on Python’s dynamic features can be particularly difficult.

PyPy: The JIT Alternative

PyPy is a Just-In-Time (JIT) compiler for Python. Unlike the standard CPython interpreter, PyPy can analyze your code while it’s running and optimize it on the fly. This can lead to impressive speed improvements, but there are some considerations to take into account:

  • Compatibility Issues: Due to how PyPy works, some Python libraries, especially those relying on C extensions, may not function correctly or have reduced performance.
  • Variable Benefits: PyPy’s effectiveness is somewhat code-dependent. While some workloads see amazing speedups, others might experience very little improvements.

C Extensions: Maximum Control, Maximum Effort

For absolute control over performance, you can write Python extensions directly in C. This allows you to bypass Python’s interpreter for critical parts of your code. However, this is the most demanding path:

  • Specialized Skillset: Requires a strong command of C programming as well as in-depth knowledge of the complex Python/C API.
  • Slower Development: Development and debugging cycles are significantly slower, as you’re working in two languages.
  • Not for the Faint of Heart: This approach is far from the data science workflow and unlikely to be feasible for most data scientists.


Exaloop addresses the dilemma of performance versus usability differently. It makes it possible to achieve native speed without sacrificing the benefits of Python for data scientists:

  • Pure Python: You continue to write standard Python code. No Cython annotations and no language extensions.
  • Optimized Libraries: Exaloop provides accelerated versions of popular data science libraries like NumPy, Pandas, and more – offering seamless speed improvements.
  • Focus on Data Science: You can spend your time extracting insights, not wrestling with complex optimization strategies. Exaloop lowers the barrier to high-performance Python, so you don’t have to worry about how to speed up Python code within your projects.

Exaloop enhances Python’s strengths, getting rid of the need to use other language plugins that are often ineffective in the long run. It allows data science teams to achieve incredible results and deliver insights much faster (10-100x speedup, compared to just Python), without the need to switch languages or learn and incorporate complex compiler toolchains.

Harnessing the Power of Parallelism

When it comes to significantly boosting Python’s performance, especially for computationally intensive data science tasks on modern hardware, one of the most effective strategies is parallelism. This involves breaking your work into smaller tasks that can execute simultaneously across multiple processing units. Let’s dive into common approaches of parallelism, their complexities, and how Exaloop empowers data scientists to streamline this process for faster Python execution.

Multiprocessing and Multithreading: Unlocking Your CPU’s Potential

Python offers built-in libraries to harness the power of your machine’s multiple CPU cores:

  • multiprocessing: This module is ideal for CPU-bound tasks that can be carried out independently of one another (e.g., heavy numerical computations, complex simulations, or machine learning model training). Multiprocessing can significantly reduce execution times by allowing processes to run genuinely in parallel, which is a good option when you are thinking about how to speed up Python code.
  • threading: This is particularly useful for I/O-bound tasks (e.g., network requests, database interactions, or file processing). Threads in Python excel in situations where your code frequently waits for external operations, allowing productive work to continue on other threads during those pauses. Importantly, Python can’t fully take advantage of multithreading because of its infamous “Global Interpreter Lock” (GIL).

Challenges of Working with Parallelism in Python

While incredibly powerful, effectively using these libraries directly often involves overcoming complexities:

  • Synchronization and Shared Data: Managing how parallel processes or threads communicate, coordinating access to shared resources, and avoiding race conditions require careful planning and can lead to error-prone code.
  • Overhead Costs: Creating and managing threads or processes consumes resources. Ensuring the tasks you divide are large enough to outweigh these costs is crucial for worthwhile performance gains.
  • Parallelizability: Not every algorithm or data workflow can easily reap the benefits of parallelism. Understanding which parts of your Python code are suitable for this approach is essential.

Scaling Out for Massive Workloads

When your datasets become truly massive or your computations exceptionally demanding, scaling beyond a single machine becomes necessary. Exaloop helps to address this with the following features:

  • Automatic Parallelization: Exaloop lets you seamlessly distribute your workload across multiple CPU cores or even GPUs, requiring minimal code modifications.
  • Easy Distributing: For scaling beyond a single machine, Exaloop integrates seamlessly with distributed computing frameworks. This allows you to harness the power of clusters without extensive configuration or rewrites.

Exaloop enables data scientists who are considering how to speed up Python code reap the benefits of parallelism, without needing to become a parallel programming or distributed systems expert.

Supercharging Performance with GPUs

Graphics Processing Units (GPUs) were initially designed to handle the vast number of calculations required for real-time graphics rendering. However, their massively parallel architecture makes them incredibly powerful for numerous other types of computations. Data scientists increasingly use GPUs for tasks like deep learning, large-scale simulations, and complex numerical analyses.

Libraries for GPU Computing

Using the power of GPUs for general-purpose computing usually involves specialized libraries:

  • CUDA: A low-level framework by NVIDIA. It provides fine-grained control over GPU programming but requires in-depth knowledge of GPU architecture.
  • PyTorch & TensorFlow: Popular deep learning frameworks that efficiently utilize GPUs, abstracting away some of the CUDA’s complexities.

Challenges of GPU Programming

Unlocking the performance benefits of GPUs when considering how to speed up Python code often comes with significant challenges:

  • Specialized Knowledge: Effective GPU programming requires an understanding of parallel programming paradigms, memory management on the GPU, and often involves the usage of a different programming model than traditional Python.
  • Code Restructuring: Python code often needs significant rewriting to fully take advantage of GPUs.
  • Hardware Limitations: Not all systems have compatible GPUs, and running GPU-enabled code often requires specific setup and configuration.

Exaloop: Effortless GPU Acceleration

Exaloop brings the benefits of GPUs to data scientists who use Python, eliminating the usual challenges associated with GPU programming:

  • Simplified Interface: Exaloop aims to accelerate applicable portions of your Python code on GPUs with minimal changes required.
  • Performance-Focused: Exaloop also focuses on the areas where GPUs excel, allowing you to reap the benefits of GPU acceleration for targeted tasks.


Python’s simplicity and rich ecosystem empower data scientists to achieve incredible results. However, performance bottlenecks can sometimes hamper the exploration process. Throughout this article, we’ve discussed strategies on how to speed up Python code, but if you’re ready to push the boundaries of what you can achieve with Python even further, join the waitlist to experience the performance boost firsthand with Exaloop.


I want to explore how to speed up Python code using parallelism, but it seems complicated. Is there an easier way?

Absolutely. While directly working with multiprocessing and threading can be complex, Exaloop simplifies parallelism for data scientists. It can automatically distribute your workload across CPU cores and it integrates with distributed computing frameworks, letting you focus on the analysis, not concurrency challenges.

Do I have to rewrite my entire Python project to see speed improvements?

Not always. The best approach for how to speed up Python code depends on your project. Start with the core optimizations mentioned in the article and use Exaloop for more substantial performance improvements.

Are there limits to how much I can speed up my Python code?

Unfortunately, yes. Factors like your algorithm, data structures, and hardware play a role. Profiling helps identify bottlenecks and tools like Exaloop push the boundaries of what’s possible within the Python ecosystem. Realistically, significant speedups (10-100x) are achievable for many data science workloads.


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