3 ms·
The USB 2.0 controller seems to be relatively inefficient on the pi 4, or at least the driver is. An RTLSDR dongle uses almost 50% CPU just shovelling samples w
by sgtnoodle 4y ago
The USB 2.0 controller seems to be relatively inefficient on the pi 4, or at least the driver is. An RTLSDR dongle uses almost 50% CPU just shovelling samples when it should only use less than 1%.
- georgia_peach 4y agoI wonder how well PXE boot + NFS shares would fare in comparison? Hasn't a lot of the USB stack been pushed into user space in more recent operating systems?
- sgtnoodle 4y agoWell, the Ethernet interface is PCI-E, so there's a good chance it would be efficient. One thing to keep in mind is that USB 3.0 is a completely different independent controller from 2.0. So, just because USB 2.0 sucks doesn't necessarily mean 3.0 does. It's just unfortunate because you would expect 2.0 to be well optimized by now. I assume the kernel driver must be using the CPU to shovel data from the USB 2.0 controller rather than DMA.