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Arthur Pastel

@apas.tel

Co-founder @codspeed.io • Building trustable and consistent performance tooling • Python, Rust, TypeScript • Creator of ODMantic • apas.tel

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05.11.2024
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Latest posts by Arthur Pastel @apas.tel

Excited to have spent some time building this inlining detection. Will come soon with an example use case showing how to leverage this new feature 🤓

29.10.2025 14:55 👍 1 🔁 0 💬 0 📌 0
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Runs just got 2 minutes faster! - Changelog - CodSpeed GitHub Action setup now uses caching to skip redundant package installations, reducing CI time by 1-5 minutes per run.

It's Friday, and all your @codspeed.io runs got 2 minutes faster😎👇
codspeed.io/changelog/20...

17.10.2025 14:06 👍 4 🔁 2 💬 0 📌 1

Excited to have it out! 🎉 This is just the first step toward adaptive instrumentation: get an overview with wall-time profiling, then zoom in with CPU simulation or other instruments to reach instruction-level detail.
This also edges us nearer to real-world sampling in production 👀

14.10.2025 14:19 👍 3 🔁 1 💬 0 📌 0

If you ship Go services and care about latency and cost, this will save you time and nasty surprises in prod!

01.10.2025 14:09 👍 1 🔁 0 💬 0 📌 0

What’s inside:
- Bench patterns that actually measure your handlers, not the harness
- A tiny DummyResponseWriter to kill recorder overhead
- b.Loop() usage with Go 1.24
- Ready-to-use GitHub Action with CodSpeed and codspeed-macro runners
- PR comments + checks to block regressions before merge

01.10.2025 14:09 👍 1 🔁 0 💬 1 📌 0
Benchmarking a Go Gin API - CodSpeed Docs Build a Gin HTTP API, write Golang benchmarks, and run them with CodSpeed in consistent CI environments

🚀🦫 New guide for Gophers: Benchmarking a Gin HTTP API

codspeed.io/docs/guides/...

01.10.2025 14:09 👍 3 🔁 3 💬 1 📌 0

Want to write faster programs?
Start with the backbone of performance: the memory allocator
Last year, @apas.tel took us deep into an often overlooked topic and made it impossible to forget. Watch it again👇🏼

05.08.2025 11:49 👍 1 🔁 1 💬 1 📌 0
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What’s faster in Rust? 🦀 Your instinct says one thing. The benchmark says something else.

@apas.tel and @adriencaccia.bsky.social are bringing a live Rust performance quiz to #EuroRust25. You don’t want to miss it!

🧵1/3

01.07.2025 12:21 👍 3 🔁 2 💬 1 📌 1
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Introducing p99.chat: the assistant for software performance optimization - Changelog - CodSpeed New updates and improvements released to Codspeed.

Learn more: codspeed.io/changelog/20...

05.06.2025 12:48 👍 1 🔁 0 💬 0 📌 0
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Announcing p99.chat, the assistant for software performance optimization 🚀

Describe your performance challenge, share your code, and p99 will analyze, instrument, and visualize the results, cutting the traditional setup overhead down to seconds!

05.06.2025 12:48 👍 4 🔁 1 💬 1 📌 2
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We’re at @pyconit.bsky.social with @adriencaccia.bsky.social!
We’ll quizz you on Python performance again tomorrow! See you in room lasagna at 11:45!

30.05.2025 20:56 👍 1 🔁 0 💬 0 📌 0
The Impact of Memory Allocators on Performance: A Deep Dive - Arthur Pastel | EuroRust 2024
The Impact of Memory Allocators on Performance: A Deep Dive - Arthur Pastel | EuroRust 2024 YouTube video by EuroRust

🦀 @apas.tel - The Impact of Memory Allocators on Performance

Memory allocators are often overlooked. But Arthur makes the case that they’re a key lever for performance in Rust. Learn how they work and when to care.

🧵 5/11

📺 Watch: youtu.be/pJ-FRRB5E84

15.05.2025 08:20 👍 1 🔁 1 💬 1 📌 0
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First Class Bazel Support for C++ - Changelog - CodSpeed New updates and improvements released to Codspeed.

We just improved our C++ integration. Now with first-class Bazel support for larger projects!

codspeed.io/changelog/20...

07.05.2025 15:30 👍 0 🔁 0 💬 0 📌 0

We just released support for C++ benchmarks, enabling the use of our google benchmark compatibility layer to measure the performance of C++ codebases!

Learn more: codspeed.io/changelog/20...

27.03.2025 14:54 👍 0 🔁 1 💬 0 📌 0
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Free Plan and Macro Runners Now Globally Available - Changelog - CodSpeed New updates and improvements released to Codspeed.

Now, even small teams and indie devs can get reliable, high-precision performance insights without breaking the bank.

Learn more: codspeed.io/changelog/20...

04.03.2025 15:56 👍 0 🔁 0 💬 0 📌 0
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Super excited about our latest changes to make performance testing more accessible! Two significant changes:

✅ The Free plan now includes private repositories (up to 5 users)
✅ Macro Runners are now globally available (bare-metal ARM64, 16 cores, 32GB RAM) with 120 min/month included for free

04.03.2025 15:56 👍 0 🔁 0 💬 1 📌 0
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Faster Workflows with Sharded Benchmarks - Changelog - CodSpeed New updates and improvements released to Codspeed.

Check it out: codspeed.io/changelog/20...

28.02.2025 15:24 👍 0 🔁 0 💬 0 📌 0
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We now support sharded benchmark execution to provide even faster performance feedback!

28.02.2025 15:24 👍 2 🔁 1 💬 1 📌 0
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GitHub - karlrupp/microprocessor-trend-data: Data repository for my blog series on microprocessor trend data. Data repository for my blog series on microprocessor trend data. - karlrupp/microprocessor-trend-data

Source: https://github.com/karlrupp/microprocessor-trend-data

19.02.2025 09:48 👍 0 🔁 0 💬 0 📌 0
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But physics is catching up. As transistors shrink, heat and power constraints limit clock speed gains. But to keep Moore’s Law going, we stack more cores. GPUs push this further with thousands of parallel cores, mentioning exponential performance increase but omitting the implementation complexity.

19.02.2025 09:48 👍 0 🔁 0 💬 1 📌 0
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Single-core performance gains have largely plateaued. That means no more relying on “free” hardware speed boosts. CPUs haven't stopped improving, but we must actively tap into new architectures. Concurrency, SIMD, and thoughtful optimizations can still unlock impressive speedups.

19.02.2025 09:48 👍 0 🔁 0 💬 1 📌 0

We can expect the same for most compiled languages. Though, when dealing with an interpreted language, this becomes much harder to optimize before any specialization or JIT compilation.

17.02.2025 14:48 👍 0 🔁 0 💬 0 📌 0
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`x * x` generates exactly the same assembly as `x.pow(2)` in Rust and this goes even beyond powers of 2, thanks to LLVM loop unrolling and exponentiation by squaring.

17.02.2025 14:48 👍 1 🔁 0 💬 1 📌 0
CodSpeed showing PR performance improvements between 38% for frozen class to 52% for make_class.

CodSpeed showing PR performance improvements between 38% for frozen class to 52% for make_class.

https://codspeed.io is pretty cool and class creation will be 38–52% faster in attrs 25.2.0

https://github.com/python-attrs/attrs/pull/1407

16.02.2025 09:50 👍 13 🔁 2 💬 3 📌 0

So for VM bytecode instrumentation, external execution path like native FFI calls need specific handling. Just like system calls need specific handing for performance measurement with native binary instrumentation.

13.02.2025 23:46 👍 0 🔁 0 💬 0 📌 0

The big issue with such an approach is that the instrumentation is limited to the interpreter itself while for native binary instrumentation the boundary is system calls and only the user space can be instrumented.

13.02.2025 23:46 👍 1 🔁 0 💬 1 📌 0

Kudos to Nikolai Vazquez for building such an intuitive benchmarking framework. We hope to contribute as much as we can to the project!

13.02.2025 15:59 👍 0 🔁 0 💬 0 📌 0
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Divan Support for Rust - Changelog - CodSpeed New updates and improvements released to Codspeed.

We just released a Divan 🛋️ integration. So far, this is the best developer experience you can hope for building performance tests in Rust 🦀!
codspeed.io/changelog/20...

13.02.2025 15:59 👍 4 🔁 2 💬 1 📌 0

Yes. First time but it was quite simple getting started

13.02.2025 07:06 👍 1 🔁 0 💬 1 📌 0
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Started hacking on a small TUI for managing EC2 instances and SSH connections. Can’t wait to ditch AWS Console's clunkiness.

12.02.2025 22:21 👍 0 🔁 0 💬 1 📌 0