PyPy/RPython contributor. Half time teaching at Uni Düsseldorf. Works on dynamic language implementations. Love street art and art in public spaces, hiking, reading. they/themhttps://bsky.app/profile/cfbolz.bsky.socialhttps://bsky.app/profile/cfbolz.bsky.social/post/3m6peztxspk2u@tartanllama.xyz Building a Debugger got a review in c't, a big German computer magazine:28 Nov 2025 17:13 +0000at://did:plc:cozhpsozipz5kcdqhwsipwdf/app.bsky.feed.post/3m6peztxspk2uhttps://bsky.app/profile/cfbolz.bsky.social/post/3m3azm2xtb224Interpreter alignment chart15 Oct 2025 19:56 +0000at://did:plc:cozhpsozipz5kcdqhwsipwdf/app.bsky.feed.post/3m3azm2xtb224https://bsky.app/profile/cfbolz.bsky.social/post/3lrfe6j2mdc2i"How slow is the tracing interpreter of PyPy's meta-tracing JIT?" https://cfbolz.de/posts/speed-of-tracing/ Spoiler: for the microbenchmark I tried, the slowdown of the meta-tracing interpreter is about 900x12 Jun 2025 07:04 +0000at://did:plc:cozhpsozipz5kcdqhwsipwdf/app.bsky.feed.post/3lrfe6j2mdc2ihttps://bsky.app/profile/cfbolz.bsky.social/post/3lpoygdu7gk2n@keleshev.com not sure whether you already saw, but Compiling to Assembly from Scratch got a review in c't 9/25 (the largest German IT magazine)21 May 2025 16:09 +0000at://did:plc:cozhpsozipz5kcdqhwsipwdf/app.bsky.feed.post/3lpoygdu7gk2nhttps://bsky.app/profile/cfbolz.bsky.social/post/3lmfhvfn5uc2r'Doing the Prospero-Challenge in RPython' new blog post on the PyPy blog: https://pypy.org/posts/2025/04/prospero-in-rpython.html09 Apr 2025 17:04 +0000at://did:plc:cozhpsozipz5kcdqhwsipwdf/app.bsky.feed.post/3lmfhvfn5uc2rhttps://bsky.app/profile/cfbolz.bsky.social/post/3liywpqjdsc22New blog post by my excellent master student Christoph Jung: "Low Overhead Allocation Sampling with VMProf in PyPy's GC" https://pypy.org/posts/2025/02/pypy-gc-sampling.html Hopefully the first in a series about his work on a sampling allocation profiler for PyPy25 Feb 2025 13:09 +0000at://did:plc:cozhpsozipz5kcdqhwsipwdf/app.bsky.feed.post/3liywpqjdsc22https://bsky.app/profile/cfbolz.bsky.social/post/3liaenovfa22tI needed something quick and dirty to count the number of malloc calls in some C programs, and the total size of the allocated memory. @pablogsal.com very helpfully shared some LD_PRELOAD code with me, which solved the problem 🙏 https://gist.github.com/cfbolz/12ff1a570b23e57d001fff43120e458715 Feb 2025 18:42 +0000at://did:plc:cozhpsozipz5kcdqhwsipwdf/app.bsky.feed.post/3liaenovfa22t