Python Performance Optimization: Understanding CPython Internals

Most "Senior" developers are just library glue-coders. They write x = [] and think they’re done. They have no idea they just triggered a cascade of C-level events in obmalloc.c. If you don't understand the True Cost of your abstractions, you aren't an engineer. You're a hobbyist with a paycheck. While others are busy memorizing frameworks, I spent my weeks in the CPython C-source code. I stopped guessing and started knowing: ❌ Stop wondering why your RAM is leaking: I break down the "High-Water Mark" problem and why Python never gives your memory back to the OS. ❌ Stop blaming the GIL: I explain how Python 3.13 is finally killing it and what "Immortal Objects" actually mean for your thread safety. ❌ Stop writing O(n²) by accident: If you don't know why an int takes 28 bytes, you can't optimize for scale. I’m done with surface-level tutorials. This is for the 5% who want to engineer at the runtime level. The missing manual for the other 95% is here: https://lnkd.in/eVbYSVVj #Python #CPython #SoftwareEngineering #Performance #SaskatoonTech #Backend

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Great deep dive! The high-water mark issue is something I've run into in long-running Django services — memory creeps up but never comes back down. Switching to connection pooling with pgbouncer and being more deliberate about queryset chunking helped a lot. Excited to see where the free-threaded Python 3.13 goes — the Immortal Objects approach is a clever workaround for refcount overhead in concurrent code. Thanks for sharing!

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