iiinova — where your digital self keeps evolving

Reposted by Felix Geisendörfer

thepudds @thepudds.bsky.social · 10/09/2026

I’m very, very happy to share that I have just joined the core Go team at Google to work on the Go runtime and compiler! I’ve been pitching in as an external contributor since 2018, but now my very enjoyable hobby is becoming my day job 😅 (Also, my name is PJ 👋)

121868

Felix Geisendörfer @felixge.de · 02/06/2026

If anybody with connections to the V8/Chrome team is reading this, my colleague Attila is trying to find a reviewer for a patch to improving profiling. Many thanks in advance for any leads 🙇🏻‍♂️ chromium-review.googlesource.com/c/v8/v8/+/78...

chromium-review.googlesource.com

Gerrit Code Review

010

Felix Geisendörfer @felixge.de · 06/05/2026

PSA: Green Tea GC in go1.26 is incredible 🚀 This is what we saw for two big Go services. We'll try to gather more data and share it soon.

3377

Felix Geisendörfer @felixge.de · 04/05/2026

I just published a proposal for a new RSS profile type for Go. It aims to solve the issue that the heap profile typically shows < 50% of process RSS, which is very confusing. It should also help to quickly identify when memory usage is dominated by cgo. github.com/golang/go/is...

github.com

proposal: runtime/pprof: add a rss profile type · Issue #79179 · golang/go

This is a proposal to introduce a new "rss" profile type to runtime/pprof to provide Go users with a holistic breakdown of their program's memory usage. Problem Statement As part of incident respon...

2255

Felix Geisendörfer @felixge.de · 30/04/2026

In exchange for 18 minutes of your time, you can get an elevator pitch about why you should be using pi (instead of claude) and perhaps more importantly, one of the sanest takes on using AI effectively 🔥 www.youtube.com/watch?v=Rjfb...

youtube.com

Building pi in a World of Slop — Mario Zechner

YouTube video by AI Engineer

2286

Felix Geisendörfer @felixge.de · 31/03/2026

The OpenTelemetry Profiles Signal is now in Alpha 🚀 This is a big step towards making Continuous Profiling in production available to the whole industry. And given the rise of AI coding, this couldn't come at a better moment in time ... 🧵

Florian Lehner and Felix Geisendörfer presenting "The Fourth Pillar Arrives: OpenTelemetry Profiling Alpha in Action" at KubeCon EU

2161

Reposted by Felix Geisendörfer

Paul Bauer @bauer.codes · 25/03/2026

People that strip debug symbols are not to be trusted.

021

Felix Geisendörfer @felixge.de · 22/03/2026

I’m headed to KubeCon Amsterdam where I’ll be talking about the otel profiling signal graduating to alpha stability. HMU if you want to chat about otel, go, o11y, profiling or anything else. I’m in town until Thursday night.

070

Felix Geisendörfer @felixge.de · 10/03/2026

.git/info/exclude is one of my favorite git features, but I'm always surprised when I talk to people who never heard about it. It basically allows you to add stuff to .gitignore without modifying the file. Great for ad-hoc ignoring some files created during debugging.

2252

Felix Geisendörfer @felixge.de · 07/03/2026

I used vim exclusively for 10+ years. But when LLMs came up, I ditched it for VS Code and later Cursor as it was the path of least resistance. But given the advancements of claude et al, it's time to go back. neovim + tmux + jjui - let's go.

2260

Reposted by Felix Geisendörfer

Johannes Bechberger @mostlynerdless.de · 13/02/2026

Redact sensitive data from Java Flight Recorder and JVM crash logs with jfr-redact, a tool for safely sharing profiling and error files: mostlynerdless.de/blog/2026/02...

mostlynerdless.de

Redacting Sensitive Data from Java Flight Recorder Files - Mostly nerdless

Redact sensitive data from Java Flight Recorder and JVM crash logs with jfr-redact, a tool for safely sharing profiling and error files.

073

Felix Geisendörfer @felixge.de · 06/01/2026

Just spend like 20 minutes debugging why claude code notifications don't work. Turns out they fire after a hard coded 60 second timeout. I don't get it, I thought I'm supposed to feed this thing with input as fast as possible? github.com/anthropics/c...

github.com

[FEATURE] Configurable timeout for idle_prompt notification hook · Issue #13922 · anthropics/claude-code

Preflight Checklist I have searched existing requests and this feature hasn't been requested yet This is a single feature request (not multiple features) Problem Statement The idle_prompt notificat...

130

Reposted by Felix Geisendörfer

Jeff Dean @jeffdean.bsky.social · 19/12/2025

My colleague Sanjay Ghemawat & I have done a fair bit of performance tuning of various pieces of code. We wrote an internal Performance Hints document ~2 years ago as a way of identifying some general principles & we've recently published a version of it externally. Doc: abseil.io/fast/hints.h...

213225

Reposted by Felix Geisendörfer

VLDMR VRNKN @vladimir.varank.in · 15/12/2025

Profiling Request Latency with Critical Path Analysis, @felixge.de @ GopherCon 2025 www.youtube.com/watch?v=BayZ...

youtube.com

GopherCon 2025: Profiling Request Latency with Critical Path Analysis - Felix Geisendörfer

YouTube video by Gopher Academy

1174

Felix Geisendörfer @felixge.de · 16/12/2025

The talk @florianl.bsky.social and I submitted has been accepted at KubeCon 2026 in Amsterdam. 🎉 Small wrinkle: The talk says that the profiling signal is in alpha … which is not true yet. Fear driven development will continue until reality and talk description are aligned!

162

Felix Geisendörfer @felixge.de · 10/12/2025

A small productivity hack I use every day. gist.github.com/felixge/ce96...

050

Reposted by Felix Geisendörfer

Anton Zhiyanov @antonz.org · 26/11/2025

Accepted! Go 1.26 will introduce per-state goroutine metrics: running, waiting, in syscalls, etc. Developers can use them to catch problems early without needing full traces. antonz.org/accepted/gor...

antonz.org

Go proposal: Goroutine metrics

Export goroutine-related metrics from the Go runtime.

1225

Reposted by Felix Geisendörfer

Nick Ripley @nsrip.com · 23/11/2025

Small contribution just before the Go 1.26 freeze: go.dev/cl/610815 removes the hard-coded 100ms sleep from the CPU profiler for most platforms. This will make it more efficient and unblock deeper call stacks. As a bonus, uncovered and fixed an 8 year old bug in the profiler go.dev/cl/722940 :)

0354

Reposted by Felix Geisendörfer

Michael Knyszek @michael.express · 20/11/2025

My talk from GopherCon 2025 about Green Tea is up on YouTube! www.youtube.com/watch?v=gPJk...

youtube.com

GopherCon 2025 - Advancing Go Garbage Collection with Green Tea - Michael Knyszek

YouTube video by Gopher Academy

13511

Reposted by Felix Geisendörfer

Neal Lathia @neallathia.bsky.social · 25/10/2025

"It has, with generative code, become harder and harder to strive towards the lions because the models produce code that is, quite literally, mid" - beautiful post by @vickiboykis.com newsletter.vickiboykis.com/archive/i-wa...

newsletter.vickiboykis.com

I want to see the claw

I respect quality software and the people who write it. And, I’ve invested years of my life in working on becoming one of these people (even if the journey...

2285

Reposted by Felix Geisendörfer

Steve Klabnik @steveklabnik.com · 22/10/2025

I see a future in #jj-vcs: steveklabnik.com/writing/i-se...

steveklabnik.com

I see a future in jj

Blog post: I see a future in jj by Steve Klabnik

6738448

Felix Geisendörfer @felixge.de · 28/09/2025

Watching "stupid jj tricks" from JJ con 2025 live right now. Tune in: www.youtube.com/watch?v=WWNh...

youtube.com

JJ Conference 2025

YouTube video by GerritForge TV

061

Felix Geisendörfer @felixge.de · 17/09/2025

I need to start a critical path analysis art gallery soon. The kind of stuff goroutines get up to behind the scenes can be truly fascinating.

070

Felix Geisendörfer @felixge.de · 17/09/2025

I'm starting to get better at leveraging AI agents for the kind of low-level stuff I'm doing sometimes. Example: Asked opus to explain some runtime internals, and then turn the analysis into a nice human-readable markdown output that I can use to explain a code change I'm making to a colleague.

140

Reposted by Felix Geisendörfer

Go @golang.org · 16/09/2025

Hi folks, it’s survey time! We’d love to learn more about how you use Go and what could be improved. Share your feedback via our annual developer survey at google.qualtrics.com/jfe/form/SV_.... It should take 10 - 20 minutes to complete, and will be open through September 30. Thank you! #golang

google.qualtrics.com

Go Developer Survey 2025

Share your feedback about developing software with Go.

05731

Reposted by Felix Geisendörfer

Ari Arnbjörnsson @flassari.bsky.social · 11/09/2025

Profile.

8795153

Felix Geisendörfer @felixge.de · 11/09/2025

My usual workflow is firing off the same query in ChatGPT 5 and Gemini 2.5 Pro these days. Typically they align, but one answer is better than the other. But it turns out no amount of AI can solve the "too many chefs in the kitchen" problem 😂.

010

Felix Geisendörfer @felixge.de · 11/09/2025

This is a fantastic week. A lot of stuff I've been hoping to accomplish, and wasn't sure if I could, seems to finally be coming together. And to top it off, Spotify just pulled an incredible "Discover Weekly" playlist out of the hat. Good times 🎶

140

Felix Geisendörfer @felixge.de · 11/09/2025

Managed to write a reproducer for a non-trivial bug last night. Old me would have been excited and stayed up late trying to fix it. These days I know this is the best time to go to sleep. And indeed, the solution came to me while falling asleep. Wrote it up this morning - works 👍🏻

1120

Reposted by Felix Geisendörfer

florianl @florianl.bsky.social · 06/09/2025

I'm excited to see that github.com/florianl/go-tc reached 500 stars on GitHub! It all began as a way for me to explore loading an eBPF program in pure Go via the traffic control API of the Linux kernel, and it's awesome to see so many people finding it useful. Thanks everyone!

142

Reposted by Felix Geisendörfer

Michael Pratt @prattmic.com · 04/09/2025

“jj undo can now undo multiple operations progressively by calling it repeatedly, whereas previously, running jj undo twice was previously a no-op (it only undid the last change).” 😮 It seems Christmas came early this year. github.com/jj-vcs/jj/re...

github.com

Release v0.33.0 · jj-vcs/jj

About jj is a Git-compatible version control system that is both simple and powerful. See the installation instructions to get started. Release highlights jj undo is now sequential: invoking it m...

1152

Reposted by Felix Geisendörfer

deadprogram @deadprogram.com · 28/08/2025

Gotta say @felixge.de has very top notch diagrams in this presentation! #golang #gopherCon

1131

Felix Geisendörfer @felixge.de · 21/08/2025

I just took my jj game to the next level by adopting the megamerge workflow. What it allows me to do is split a lot of my work into independent PRs (CLs), but work on a local tree that reflects the state of the repo as if all of them had already been merged.

4120

Reposted by Felix Geisendörfer

Justin @jaffray.bsky.social · 18/08/2025

NULL BITMAP: Using Huffman Coding for Sampling Discrete Distributions: buttondown.com/jaffray/arch...

1135

Reposted by Felix Geisendörfer

GopherCon @gophercon.com · 18/08/2025

⏳ ONE. WEEK. TO. GO. 🎉 The countdown is officially ON—#GopherCon is just around the corner! Don’t wait until the last minute—lock in your pass now and get ready to join us in NYC for the biggest #golang celebration of the year! 👉 www.gophercon.com #GopherConOrBust #GophersUnite

0125

Felix Geisendörfer @felixge.de · 16/08/2025

Having fun using pikchr to generate diagrams for my critical path analysis talk at GopherCon US.

2290

Reposted by Felix Geisendörfer

Filippo Valsorda @filippo.abyssdomain.expert · 12/08/2025

The Go 1.25 change I am most excited about is the new synctest package. How I think about it is as a way to deflake tests by simulating an infinitely fast processor (because time doesn’t move until all work is done), and then shorten them by compressing time (because time jumps once it moves).

27713

Reposted by Felix Geisendörfer

Go @golang.org · 12/08/2025

🎊 Go 1.25.0 is released! 📝 Release notes: go.dev/doc/go1.25 ⬇️ Download: go.dev/dl/#go1.25.0 #golang

$ go install golang.org/dl/go1.25.0@latest
$ go1.25.0 download
Downloaded 0.0% ( 0 / 58130695 bytes) ...
Downloaded 50.0% (29065347 / 58130695 bytes) ...
Downloaded 100.0% (58130695 / 58130695 bytes)
Unpacking go1.25.0.freebsd-arm.tar.gz ...
Success. You may now run 'go1.25.0'
$ go1.25.0 version
go version go1.25.0 freebsd/arm

418954

Reposted by Felix Geisendörfer

GopherCon @gophercon.com · 05/08/2025

Why is your code allocating memory? How does the Go compiler see the world? Join Go contributor @thepudds.bsky.social for a deep dive into escape analysis—the part of the compiler that decides whether your data stays on the stack or takes the more expensive trip to the heap. 🎟️ www.gophercon.com

064

Reposted by Felix Geisendörfer

GopherCon @gophercon.com · 01/08/2025

🧭 CPU profiling isn’t telling you the whole story. Let’s fix that! Join @felixge.de as he introduces a novel approach to analyzing Go request latency using critical path analysis—one that goes beyond traditional CPU profiling, logs, or traces. 🎟️ www.gophercon.com #GopherConOrBust #golang

0102

Felix Geisendörfer @felixge.de · 31/07/2025

Wrote up a small proposal to make it easier to test code that is processing #golang execution traces using the x/exp/trace package.

170

Felix Geisendörfer @felixge.de · 30/07/2025

Few things are more cursed than the way VS Code extensions determine which local development tools to use. This is especially true when using remote hosts via ssh.

110

Felix Geisendörfer @felixge.de · 21/07/2025

German word of the day: Verschlimmbessern = "Trying to make something better, but actually making it worse in the process" A lot of engineering work falls into this category. Sometimes the answer is that there is value in leaving a problem unsolved.

2436