After working on ZGC for a decade, I’m happy to announce that I’m publishing a book about ZGC in JDK 25. It ships 22 May (www.taylorfrancis.com/books/mono/1...) and is being published by Taylor & Francis. You should get a copy if you want to learn more about ZGC. It’s available for pre-order now.

Very cool research made it into TruffleRuby!

[email protected] and I are looking for a PostDoc to work on our EPSRC Project "INDIMO: Invariant Discovery and Monitoring for Message-Passing Programs". If you know someone, or are interested, please reach out! A few details here: jobs.royalholloway.ac.uk/Vacancy.aspx...

[email protected] and I are looking for a PostDoc to work on our EPSRC Project "INDIMO: Invariant Discovery and Monitoring for Message-Passing Programs". If you know someone, or are interested, please reach out! A few details here: jobs.royalholloway.ac.uk/Vacancy.aspx...

Koichi gave a talk at VMIL about it: youtu.be/pqDMne677Ww?... The code is at github.com/ko1/astro naruby uses the Prism C API for parsing: github.com/ko1/astro/tr...

Last year I had the pleasure to review and contribute to this paper by @ko1s.bsky.social: atdot.net/~ko1/activit... It's a tiny framework to partial evaluate AST interpreters written in C. The paper uses the example of a minimal subset of Ruby called naruby (Not A Ruby).

More PLISS speakers announced! pliss.org/2026/

Had a good inspiring break? Tell us about your latest ideas on language implementations, compilers, and VMs: 2026.programming-conference.org/home/MoreVMs... Can be just a short abstract, or something slightly more technical if preferred. Deadline in about a week, Jan 12th.

Had a good inspiring break? Tell us about your latest ideas on language implementations, compilers, and VMs: 2026.programming-conference.org/home/MoreVMs... Can be just a short abstract, or something slightly more technical if preferred. Deadline in about a week, Jan 12th.

ZJIT is available starting in Ruby 4.0! Please try it out on your test suite, maybe in a staging environment, and let us know how it goes! railsatscale.com/2025-12-24-l...

Last workday of the year for me. Down to 30 unread emails. Let's see what the new year brings 🙈

Another example of rankings being silly. Before: 4 After: 10 Yes scoped to my personal interest, but still. These "emery berger rankings" are silly.

Some university administrator set a deadline for Dec. 23rd 23:59.

I can't quite believe that we're now announcing the eighth Programming Language Implementation Summer School (PLISS), but we are --- in May next year, if you want to learn more about programming language implementations, this is the place to come!

How can we know whether a profiler is accurate? Humphrey's presentation of our paper "Divining Profiler Accuracy: An Approach to Approximate Profiler Accuracy Through Machine Code-Level Slowdown" is now online: www.youtube.com/watch?v=U-7P...

How can we know whether a profiler is accurate? Humphrey's presentation of our paper "Divining Profiler Accuracy: An Approach to Approximate Profiler Accuracy Through Machine Code-Level Slowdown" is now online: www.youtube.com/watch?v=U-7P...

Tomorrow end of day, anywhere on earth, is our "pre-holiday" deadline for MoreVMs: 2026.programming-conference.org/home/MoreVMs... Submit your papers, talk proposals, or experimental setups now and enjoy some time off!

You want to slow down your programs? This is the right talk for you: www.youtube.com/watch?v=xNwu... Humphrey presenting our paper "Evaluating Candidate Instructions for Reliable Program Slowdown at the Compiler Level".

You want to slow down your programs? This is the right talk for you: www.youtube.com/watch?v=xNwu... Humphrey presenting our paper "Evaluating Candidate Instructions for Reliable Program Slowdown at the Compiler Level".

Working on your MoreVMs submission? Get inspired by this year's work presented at MPLR and VMIL! www.youtube.com/playlist?lis... www.youtube.com/playlist?lis...

First set of lectures completed in the new job. A series on "System Software" covering GC, Linkers/Loaders, Debuggers, and Text Editors. Was an interesting mix. Will have to think carefully about how to evolve it next year. Now I can fully focus on the remaining Compiler Construction lectures ☺️

The MoreVMs workshop has two submission deadlines this time: Pre-Holiday: 17 December 2025 Post-Holiday: 12 January 2026 We know, nothing happens without a deadline.⌛️💣 So, there you go. You made me do it! 🤣😅 😇 Anyway, pick one and submit! 🧑‍🔬🧪✍️📜 2026.programming-conference.org/home/MoreVMs...

The MoreVMs workshop has two submission deadlines this time: Pre-Holiday: 17 December 2025 Post-Holiday: 12 January 2026 We know, nothing happens without a deadline.⌛️💣 So, there you go. You made me do it! 🤣😅 😇 Anyway, pick one and submit! 🧑‍🔬🧪✍️📜 2026.programming-conference.org/home/MoreVMs...

Was looking at some older slides and found a claim that copying text around for a text editor is only practical for <256chars. It's Friday, let's see whether this is a "current" assessment, considering only the text, and none of the other things an editor does.

Benchmarking Language Implementations: Am I doing it right? Get Early Feedback! stefan-marr.de/2025/11/expe... MoreVMs'26 is looking for submission of "experimental setups" to help language implementation researchers to avoid common benchmarking pitfalls. Submit something either Dec 17 or Jan 12.

Benchmarking Language Implementations: Am I doing it right? Get Early Feedback! stefan-marr.de/2025/11/expe... MoreVMs'26 is looking for submission of "experimental setups" to help language implementation researchers to avoid common benchmarking pitfalls. Submit something either Dec 17 or Jan 12.

Today at #ase2025: “The fault in our stats”, or how the majority of notebooks fails to check even the most basic statistical assumptions

We are thrilled to announce that our NEW Large Language Model will be released on 11.18.25.

The Virgil compiler interprets its SSA representation directly, as compile-time initialization allows the full language--a simplification after two generations of customized interpreters. It does basically what Mike wrote, except gotos assign the values of phis instead of looking them up.

LuaJIT 3 might interpret an SSA-based program representation (possibly with a more optimized interpreter for platforms without JIT compilation) www.freelists.org/post/luajit/...

MPLR'26 will be in Brussels! The deadline is sooner than usually, March 6th. Please get your papers ready early! MPLR is interested in all things VMs, Language Implementation, Compilers, Interpreters, and Tooling! 2026.ecoop.org/home/mplr-20... They'll colocate again with ECOOP and ICOOOLPS!

MPLR'26 will be in Brussels! The deadline is sooner than usually, March 6th. Please get your papers ready early! MPLR is interested in all things VMs, Language Implementation, Compilers, Interpreters, and Tooling! 2026.ecoop.org/home/mplr-20... They'll colocate again with ECOOP and ICOOOLPS!

Somewhat delayed because of Covid, I'm finally going to give my "inaugural lecture", which is a short, hopefully accessible, public talk: in my case "Some things I've learned about software"! All are welcome!

Could you be our next Head of School? We're seeking an innovative, forward-thinking leader to join us in this academic leadership role, accountable for providing a coherent academic vision and direction for the School. Apply by 30 November: www.jobs.gla.ac.uk/job/professo...

Just told my course staff that variable-length arrays have been part of C since “the late 1900s”.

Four lectures in, not a single one recorded properly. I truly reached the professorial level, and started conforming to the stereotype... I used to joke that professors lose their practical skills. Now, I am living it. 🤦🏻‍♂️

To teach the Deutsch-Schorr-Waite pointer reversal GC marking algorithm or not...

Last week I presented at #MPLR2025 our work on #TornadoInsight - an #opensource tool for static & dynamic analysis of #Java code using #TornadoVM on #GPUs. The presentation is on YouTube: 🎥 Talk: youtube.com/live/sJZtDHw... The tool is available on GitHub & JetBrains Marketplace!

Are there any benchmarks (etc) which show the costs of the SysV x64 ABI relative to a somewhat-or-perfectly-optimal ABI for that program? [Not for single microbenchmarks, because I can definitely create horrible overheads there, but on larger programs / benchmarks.]

Computing @ Imperial are hiring four Ass. / Assoc. Profs! Priority areas: - PL - Systems - Security - Software Eng. - Computer Architecture - Theoretical Computer Science Applications from individuals from underrepresented groups especially welcome! www.imperial.ac.uk/jobs/search-...

Humphrey is now presenting his work titled: Divining Profiler Accuracy: An Approach to Approximate Profiler Accuracy Through Machine Code-Level Slowdown My short take on our work, incl. link to paper: stefan-marr.de/2025/10/can-...

Can We Know Whether a Profiler is Accurate? Spoiler: yes we can! But it took us figuring out a way to work around the fundamental observer effect. stefan-marr.de/2025/10/can-... If you're at SPLASH, don't miss our talk at VMIL today and at OOPSLA on Saturday!

For those of you in Singapore, Jake is at SPLASH and presenting the paper on Saturday. He's friendly, and on the job market -- please find him and say hello!

New paper with @jakehughes.uk : Garbage Collection for Rust: The Finalizer Frontier. There are lots of GCs for Rust: we tried pushing as far as we could in a new direction, particularly looking at what can be done about the headache that is finalizers.

Last talk VMIL talk for 2025: RuntimeSave: A Graph Database of Runtime Values

Next VMIL talk Memory Tiering in Python Virtual Machine

Next VMIL talk MaTSa: Race Detection in Java

Next VMIL talk: TEAL: a Total Expressive Assembly Language

Next VMIL talk: Heterogeneous translation of Scala-like function types in Java-TX

The VMIL keynote The Wild West of post-POSIX IO Interfaces