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Stefan Marr @smarr

Interpreters, compilation, concurrency, and debugging tools.

Joined June 2008
  • Tweets 9,679
  • Following 460
  • Followers 2,001
471 Photos and videos
Stefan Marr retweeted
River Dillon
@river__dillon
Jun 10
The next London Systems group meeting will be July 2nd! Laurence Tratt (@laurencetratt) will talk about automatically deriving JIT compilers from interpreters, and David de Rosier will talk about custom instructions in RISC-V. Come hang out and learn :)
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Stefan Marr retweeted
Laurence Tratt@laurencetratt
Jun 10
I'll be speaking at London Systems on Jul 2nd. Attendance is free, and you get a lightning talk or two as a bonus!
River Dillon
@river__dillon
Jun 10
The next London Systems group meeting will be July 2nd! Laurence Tratt (@laurencetratt) will talk about automatically deriving JIT compilers from interpreters, and David de Rosier will talk about custom instructions in RISC-V. Come hang out and learn :)
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Stefan Marr retweeted
Sam Tobin-Hochstadt@samth
Jun 1
Replying to @vardi
Genuinely, this is incredibly disappointing from what is supposedly the flagship product of our professional society.
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Might have won something. Instead of 10h with @DB_Bahn, they want me to travel 20h with them... Enjoying 10 trains and busses, instead of 3... Got rebooked "automatically" it seems. Thanks AI!
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Ugh. Past me underestimated how many experiments future me is going to run. ReBenchDB just overflowed 16bit ints on the number of trials (i.e., experiments per benchmark machine). Is this something to celebrate? The number of collected measurements already requires 24bits...
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Stefan Marr retweeted
Stefan Marr@smarr
May 14
The program of ICOOOLPS is now online: 2026.ecoop.org/home/ICOOOLPS… And today is the last day for early registrations. Interested in programming language implementation, compilation, and optimization? Join us in Brussels! Don't know what to expect? 1/2

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The program of ICOOOLPS is now online: 2026.ecoop.org/home/ICOOOLPS… And today is the last day for early registrations. Interested in programming language implementation, compilation, and optimization? Join us in Brussels! Don't know what to expect? 1/2

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... Here the MoreVMs recordings from earlier this year, and yes, in-person, the sound was perfect 🙈: youtube.com/playlist?list=PL… 2/2

MoreVMs 2026

Recordings of the MoreVMs workshop in Munich, March 2026

youtube.com
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Stefan Marr retweeted
ECOOP’26 Conference@ECOOPconf
May 7
7 days left for early registration at #ECOOP2026! Keynotes on verified compilation, 15 years of Viper, and where programming paradigms converge. Brussels, BE, June 29 – July 3. Early bird deadline: May 14th → 2026.ecoop.org/attending/reg…
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Stefan Marr retweeted
Didier Verna@didierverna
May 7
The Art, Science, and Craftsmanship of Typography The slides for my recent keynote at the <Programming> 2026 conference are now available online: didierverna.net/talks/verna.… #typography #typesetting

The Art, Science, and Craftsmanship of Typography | Didier Verna's Scientific Website

A journey through the art of setting type

didierverna.net
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Stefan Marr retweeted
Stefan Marr@smarr
May 6
Towards Least-Privilege WebAssembly Applications: Transparent Interposition for WebAssembly Components Olav Blaak talked about his approach to fine-grained security policies for Wasm components. youtu.be/a3a_le54tW0 This one was another MoreVMs'26 talk.

Towards Least-Privilege Wasm Applications: Transparent Interposition...

When a WebAssembly component is compromised, current security model...

youtube.com
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Lecture 7, and we have a recording. Some said it would be impossible. Others suggested that computers were a mistake in the first place. And sometimes I reminded myself of younger me who observed/predicted that professors have no technical skills any longer. Is it perfect? 1/2
Stefan Marr@smarr
May 4
At this point, the expectations from the students to get recordings is zero. Maybe it's a good thing. But, I won't be defeated by technology! Wish me luck 🙈
ffmpeg8 \ -probesize 50M -analyzeduration 50M -f avfoundation -capture_cursor 1 -framerate 30 -pixel_format uyvy422 -i "${SCREEN_IDX}:none" \ -probesize 50M -analyzeduration 50M -f avfoundation -framerate 30 -video_size 1920x1080 -pixel_format nv12 -i "${CAMERA_IDX}:${MIC_IDX}" \ -map 0:v -c:v h264_videotoolbox \ -vf "scale=1920:1080:force_original_aspect_ratio=decrease,pad=1920:1080:(ow-iw)/2:(oh-ih)/2:black" \ -pix_fmt yuv420p -color_range pc -b:v 5M -movflags frag_keyframe empty_moov \ "${NAME_PREFIX}_screen.mp4" \ -map 1:v -map 1:a -c:v h264_videotoolbox \ -pix_fmt yuv420p -color_range pc -b:v 2M -c:a aac_at -b:a 192k -movflags frag_keyframe empty_moov \ "${NAME_PREFIX}_webcam_mic.mp4"

ALT ffmpeg8 \ -probesize 50M -analyzeduration 50M -f avfoundation -capture_cursor 1 -framerate 30 -pixel_format uyvy422 -i "${SCREEN_IDX}:none" \ -probesize 50M -analyzeduration 50M -f avfoundation -framerate 30 -video_size 1920x1080 -pixel_format nv12 -i "${CAMERA_IDX}:${MIC_IDX}" \ -map 0:v -c:v h264_videotoolbox \ -vf "scale=1920:1080:force_original_aspect_ratio=decrease,pad=1920:1080:(ow-iw)/2:(oh-ih)/2:black" \ -pix_fmt yuv420p -color_range pc -b:v 5M -movflags frag_keyframe empty_moov \ "${NAME_PREFIX}_screen.mp4" \ -map 1:v -map 1:a -c:v h264_videotoolbox \ -pix_fmt yuv420p -color_range pc -b:v 2M -c:a aac_at -b:a 192k -movflags frag_keyframe empty_moov \ "${NAME_PREFIX}_webcam_mic.mp4"

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No! But it has slides, audio, and video. Something that eluded me since I started here... Sigh. Software...
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At this point, the expectations from the students to get recordings is zero. Maybe it's a good thing. But, I won't be defeated by technology! Wish me luck 🙈
ffmpeg8 \ -probesize 50M -analyzeduration 50M -f avfoundation -capture_cursor 1 -framerate 30 -pixel_format uyvy422 -i "${SCREEN_IDX}:none" \ -probesize 50M -analyzeduration 50M -f avfoundation -framerate 30 -video_size 1920x1080 -pixel_format nv12 -i "${CAMERA_IDX}:${MIC_IDX}" \ -map 0:v -c:v h264_videotoolbox \ -vf "scale=1920:1080:force_original_aspect_ratio=decrease,pad=1920:1080:(ow-iw)/2:(oh-ih)/2:black" \ -pix_fmt yuv420p -color_range pc -b:v 5M -movflags frag_keyframe empty_moov \ "${NAME_PREFIX}_screen.mp4" \ -map 1:v -map 1:a -c:v h264_videotoolbox \ -pix_fmt yuv420p -color_range pc -b:v 2M -c:a aac_at -b:a 192k -movflags frag_keyframe empty_moov \ "${NAME_PREFIX}_webcam_mic.mp4"

ALT ffmpeg8 \ -probesize 50M -analyzeduration 50M -f avfoundation -capture_cursor 1 -framerate 30 -pixel_format uyvy422 -i "${SCREEN_IDX}:none" \ -probesize 50M -analyzeduration 50M -f avfoundation -framerate 30 -video_size 1920x1080 -pixel_format nv12 -i "${CAMERA_IDX}:${MIC_IDX}" \ -map 0:v -c:v h264_videotoolbox \ -vf "scale=1920:1080:force_original_aspect_ratio=decrease,pad=1920:1080:(ow-iw)/2:(oh-ih)/2:black" \ -pix_fmt yuv420p -color_range pc -b:v 5M -movflags frag_keyframe empty_moov \ "${NAME_PREFIX}_screen.mp4" \ -map 1:v -map 1:a -c:v h264_videotoolbox \ -pix_fmt yuv420p -color_range pc -b:v 2M -c:a aac_at -b:a 192k -movflags frag_keyframe empty_moov \ "${NAME_PREFIX}_webcam_mic.mp4"

Stefan Marr@smarr
May 1
After the uni's browser-based lecture recording system failed in 6 different ways (it worked last term), I am running out of ideas. I guess ffmpeg is my next best option.
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Stefan Marr retweeted
ECOOP’26 Conference@ECOOPconf
May 4
⏰ Early registration for #ECOOP2026 closes May 14 (AoE) Don't miss out! 📍 Brussels, Belgium 🎤 3 keynote speakers 📄 31 top-notch papers 🛠️ 8 workshops 🎓 9 engaging ECOOP Academy talks Demos, posters & co-located events (GPCE & MPLR) 👉 2026.ecoop.org
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After the uni's browser-based lecture recording system failed in 6 different ways (it worked last term), I am running out of ideas. I guess ffmpeg is my next best option.
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Stefan Marr retweeted
Stefan Marr@smarr
Apr 28
Retaining the Renaissance: Lessons Learned For Maintainable Benchmark Suites Lubomír Bulej talk at MoreVMs'26 about keeping a benchmarking suite relevant, and what we may learn from the Renaissance project. youtu.be/SF3T0YHHZMc
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Stefan Marr retweeted
ECOOP’26 Conference@ECOOPconf
Apr 27
📢 #ECOOP2026 still has open calls! 🎬 Demos 📋 Posters 🏆 Student Research Competition 🙋 Student Volunteers Don't miss your chance to participate in Europe's longest-standing PL conference in Brussels 🇧🇪 👉 2026.ecoop.org
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