It's the memory latency, stupid

boricj

I work with another team at work that uses lots of message passing, C++ virtual methods in deeply nested class hierarchies, large DOMs and off-the-shelf C++ STL containers... on a STM32MP1, which has an in-order Cortex-A7 and a pittance of cache. On the other hand, in my team I wrote my custom C++ STL containers that allocate inline, SAX-style processing libraries and an object pool with links that use index+generations like 2000s video games... on a STM32H5 with less than a megabyte of RAM. Mechanical sympathy feels like a lost art to people I demonstrate it to... and I had to demonstrate to the first team with benchmark numbers that I would not be the bottleneck between us by orders of magnitudes.

brcmthrowaway

https://people.freebsd.org/~lstewart/articles/cpumemory.pdf Has anyone rewritten this for 2026?

drivebyhooting

I feel like the solution presented is just a clustered hashmap or “locality sensitive” if you’d like it. Still not orders of magnitude better.

happyPersonR

Shout out to the author, it seems coherent. I like flamegraphs I know folks use perf to help generate them But in the future, now that Llm is here, get and agent to check assembly, PMUs and also see what you’re doing in assembly. My 2c and happy coding to everyone :)

quotemstr

Uh, isn't this just radix-partitioned aggregation? Hierarchical (fixed two level) aggregation is old. What's novel here? Microcosm of Pivot itself I guess. I just don't get why this project exists when DuckDB and Clickhouse both exist.