Alfonso Subiotto

@polarsignals.com is joining @dash0.com! We'll be integrating continuous profiling into Dash0 and replacing ClickHouse with Great Lakes, the storage engine we built to power Polar Signals. www.polarsignals.com/blog/posts/2...

This was a fun one! For @polarsignals.com's latest hackathon, I wrote an FSST decompression CUDA kernel and then optimized it by profiling with our new GPU PC sampling feature. www.polarsignals.com/blog/posts/2...

If you're doing any performance work on GPUs, this is huge. PC sampling is a powerful tool for GPU optimization, but causes serial kernel executions. We've released production-ready continuous PC sampling so you can get GPU performance insights on your production workloads.

New Blog Alert! Learn how we overcame eBPF limits to unwind deeply nested PyTorch training stacks and learned some cools things along the way: www.polarsignals.com/blog/posts/2...

🤖Using Polar Signals Cloud and Claude Code to autonomously optimize your code every day! 📈 Also: Check out our new website! What do you think? www.polarsignals.com/blog/posts/2...

Tired of Node.js flamecharts full of `a`, `m`, and `_0x3f2`? We just shipped source maps support for Node.js profiles in Polar Signals Cloud. Just add a plugin to your build pipeline, and your profiles show the real code. Know more: www.polarsignals.com/blog/posts/2...

I'm happy to share that I will be speaking at #QConLondon on March 16 on deterministic simulation testing at Polar Signals. For anyone interested in attending: SPEAKER60QUK26 for £60 off

Claude is down. I guess I have to learn how to code again.

📢 It’s a new year so we’re announcing something new which is the Sandwich view: A way to visualize a function’s callers and callees side by side for better debugging and performance work. Read more about it here: www.polarsignals.com/blog/posts/2...

My EuroRust talk has been uploaded to YT! I cover how we architected our Rust database at @polarsignals.com as a set of state machines to enable deterministic simulation testing and catch hard-to-reproduce bugs before they hit prod.

A simple 50-line code change saves us 30% of CPU across our whole infrastructure. This is the magic of system-wide profiling with @polarsignals.com. Easy to spot, easy to fix.

🚀 We recently announced our NVIDIA CUDA always-on profiler. Check out this blog on how to try it out super quickly with your CUDA workload today!🧊 www.polarsignals.com/blog/posts/2...

Happy to share that I've been nominated to the Vortex Technical Steering Committee! It's been fun and productive switching to Vortex from Parquet as our storage format @polarsignals.com and I'm excited to continue contributing to the Vortex project. vortex.dev/blog/novembe...

🧊 New on the Polar Signals Blog — Our Delta Lake Fork Purpose-built for our continuous profiling product. In our latest post, we walk through how Delta Lake works, and the changes we've made to improve performance for our product. 👉 Read the full post: buff.ly/KwHINtO

Ever wondered how your browser devtools jumps from bundle.min.js:1:27698 → src/index.ts:73:16? 🧊 We unpack the internals of JS Source Maps: Base64 VLQ encoding, mapping deltas, and how your original TS code gets reconstructed from minified bundles. 🔗 www.polarsignals.com/blog/posts/2...

Introducing the world's first open source continuous NVIDIA CUDA profiler. Zero code changes required, low overhead, and always on.

Took advantage of the lunch break to replay this great talk by Alfonso Subiotto (@asubiotto.com) making the case for a State Machines based approach to Deterministic Simulation Testing, being used at @polarsignals.com, very interesting! Their inspiration for this: sled.rs/simulation

We're excited to be at @rustconf.com 2025! Let's talk about profiling Rust with zero compromise! #rustconf25

We recently made some performance improvements to our Flame Graph by implementing backend pre-computation and viewport culling. Read more in our latest blog post: www.polarsignals.com/blog/posts/2...

I wrote about why we should treat German string encoding/StringViews as Just Another Encoding™

Do any database systems "columnarize" the German string encoding so rather than storing a 16-byte view for each element which includes length+prefix+pointer you'd store all lengths together, prefixes together etc...? Seems like prefix operations would be more SIMD friendly.

The hardest part about writing a blog post is the introduction. Here I am, 4 hours later.

Tame the OOM killer with OOMProf, the new eBPF memory profiler for Go programs being taken out by the kernels OOM killer! www.polarsignals.com/blog/posts/2...

We're excited to share that the Parca Agent now works offline! Store CPU profiles locally when disconnected, upload when ready. Because not all computing happens in data centers. Read how we built it: www.polarsignals.com/blog/posts/2...

New storage format RFC in the works 👀 Early preview:

🚀 Today, we're excited to launch Off-CPU profiling! Check out our blog on what we needed to do to make it most useful and how you can get started with it! 🧊 www.polarsignals.com/blog/posts/2...

@metalmatze.de built an MCP server so you can hook up your agent to your profiling data. Check it out!

📔Writing our Rust database from scratch gave us a golden opportunity to implement deterministic simulation testing as a core feature. Learn about the architecture that gives us full control over DST ingredients. 🧊 www.polarsignals.com/blog/posts/2...

If you're serious about performance, you need continuous profiling in your life

Nice read about how maybe it's time to delete some tests (not your DST test though): andre.arko.net/2025/06/30/y...

This was a fun read. Speed runs building a cloud DB. Hill climbing the design can lead to a local maximum. Lots of lessons. Now I need to read their next post on the new one!

Looking forward to speaking at @eurorust.eu about the deterministic simulation testing we're doing at @polarsignals.com!

Our very own @asubiotto.bsky.social for the first time publicly talking about the DST approach we’re taking in our new database. (Blog post coming soon as well!)

Off to Systems Distributed. See you in Amsterdam!

Quis verificabit ipsos verificatores?

Claude code seems to love debugging by pointing at random code paths it doesn't understand and saying "the root cause is now clear"

We've been working hard to enhance our continuous profiling for GPUs. Learn about more metrics (like PCIe throughput) and the upcoming On-GPU profiles. If you are attending ai.engineer, come and stop by our booth S18 to discuss all of these features! www.polarsignals.com/blog/posts/2...

⚡ Flamecharts/Iciclecharts are now available on all workloads, not just the Polar Signals GPU profiling experience! Check out the blog on what Flamecharts/Iciclecharts are and how to use them on Polar Signals! 🧊 www.polarsignals.com/blog/posts/2...

No biggie, just Wikimedia running Pyrra: slo.wikimedia.org 😳😎🥳 Pretty great feeling to see how far this free time project has come. Wow.

Had the great pleasure tonight of being with Brown CS professor Tom Doeppner, who is retiring after an extraordinary 49 years of teaching. Tom -- and his legendary OS course, CS169 -- inspired multiple generations of practitioners. Thank you, Tom!

🔬 We've been researching PGO with sampling profiling data for Rust (and LLVM more generally) at Polar Signals. Check out what Tommy has found so far and stay tuned for the next posts in this series! 🧊 www.polarsignals.com/blog/posts/2...

🦀 Today, we're introducing the ability to attach arbitrary metadata to Profiling data with Async-Rust! Use this to attach the distributed tracing ID and more to your Profiling data! 🔍 www.polarsignals.com/blog/posts/2...