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--- newsletters:2024-11 [2024/12/01 03:17] – admin
+++ newsletters:2024-11 [2024/12/01 04:09] (current) – osnr
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-====== November 2024 newsletter (WIP) ======
+====== November 2024 newsletter ======
 (Our next Folk open house is [[https://partiful.com/e/eZXJm5gn0rxglOGi5Jsa|at noon on Sunday, December 15]], at our studio in East Williamsburg, Brooklyn.)
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 There's still a lot of blinking under the new evaluator, but no ghosting, and I think the blinking all now emerges from genuine failures to meet timing (the label blinks out because the program region wasn't regenerated in time for the current frame).
+Notice how the camera hits 60fps but the full-frame detection is only 20-30fps (this is using a 1080p image):
+{{:newsletters:pasted:20241201-040919.png?550px}}
 === The bugfixes and improvements ===
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       * now runs on an independent clock from the frames! every 2ms
     * hack for 'descriptor indexing' on Pi GPU so images & text work
+    * incremental tag detection to be able to hit 60fps
@@ Line 51: / Line 56: @@
 Performance (CPU, stack) profiling is most of what I'm up to now, trying to eliminate the blinking.
-I've already fixed a lot of weird issues with flamegraph profiling and made it noticeably smoother.
+I've already fixed a lot of weird issues using flamegraph profiling and made it noticeably smoother. Like replacing rand with rand_r to fix this:
+{{:newsletters:pasted:20241201-034841.png?400px}}
+I'm surprised at how much of the flamegraphs are just threading stuff, not Tcl-bound. Maybe I'm misreading and need different graphs (the mutex time is just time when it's scheduled off the CPU, not wasted time). Here is an average worker thread:
+{{:newsletters:pasted:20241201-034557.png?600px}}
-I'm surprised at how much of the flamegraphs are just threading stuff, not Tcl-bound. Maybe I'm misreading and need different graphs.
+Now working on actually using [[https://github.com/wolfpld/tracy|Tracy]] to get a full view of what's going on, which I've been curious about for years.
 == Heap profiling ==
-There are still persistent and pretty bad memory leaks on folk2, from 10MB to 200MB per second depending on how much stuff is out. I want to get to these soon after fixing the performance stuff.
+There are still persistent and pretty bad memory leaks on folk2, from 10MB to 200MB per second depending on how much stuff is out. I want to get to these soon after I fix the performance stuff.
 === Various unsuccessful quests ===
   * Heap profiling with gperftools
+    * Too slow, doesn't seem to detect most of the heap?
   * mimalloc arenas
+    * Might still be useful for images and stuff, but we'd need to migrate the arena between matches and statements as statements get reused, it's more complicated than expected
   * Sealed Tcl objects
     * I had been hoping to do this forever -- it seems elegant and cool and efficient -- but it turned out to be much harder than expected when I looked at it -- would need to change a lot of callsites in Jim Tcl (anywhere it shimmers an object) to make it work, or do horrible hacks with COW pages.
+    * {{:newsletters:pasted:20241201-040815.png?550px}}
   * CPU-oriented scheduling
   * Spinlocks
     * [[https://www.realworldtech.com/forum/?threadid=189711&curpostid=189723|Linus is probably right]]
     * I got too excited since we have fairly tight locking discipline in folk2
+    * Look at all this spinning; it's not an improvement over mutexes:
+      * {{:newsletters:pasted:20241201-034649.png?500px}}
 ==== RFID localization ====
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 These are all 'minor' additions to the gadget that I want to throw into future revisions (and have ordered parts for).
-I've been talking about a trigger button for a while. Realized that some commercially available camera grips just use an audio jack. This seems good. Threw it into part orders and will probably throw it into next design rev.
+I've been talking about a trigger button for a while, but been blocked by figuring out what connectors/cables to use so the handle grip with trigger button can be removable (in case you want to mount onto an arm). Realized that [[https://www.amazon.com/CB-800-Universal-Pistol-Shutter-Release/dp/B01KMKZ3AY/|some commercially available camera grips just use a 2.5mm jack for a button output.]] This seems good. Let's use a 3.5mm audio jack (TRRS) instead. Threw that into part orders and will probably throw it into next design rev.
-I'm thinking about the Super Mario Galaxy Wii remote interactions and sounds for some reason.
+as for what to do with the trigger button, I'm thinking about the Super Mario Galaxy Wii remote interactions and sounds...
 (I also threw a speaker into part orders.)
@@ Line 148: / Line 164: @@
   * Gadget autoadjust exposure maybe?
   * RFID
+  * Actually revisit video support
+  * More convenient shader language
+  * Experiment with more tangible papercraft interface elements for Folk programs (using cardboard, rubberbands, etc.)
+  * Revisit a bunch of smaller system improvements that we've had in the backlog for a while
 ===== Links we've enjoyed =====