3 ms·
How do you avoid buffering reads through DRAM and also avoid using mmap? Like even io_uring has to get data off the device (which is probably memory mapped) and
by dataangel 4y ago
How do you avoid buffering reads through DRAM and also avoid using mmap? Like even io_uring has to get data off the device (which is probably memory mapped) and into DRAM, so maybe I'm just not understanding what you mean.
- gpderetta 4y agoSome PCI devices can DMA directly into/from the CPU cache bypassing memory. See intel direct IO for example.
- namibj 4y agoYou can for example use a controller memory buffer with NVMe and just access the data over mapped PCIe, or you get it to DMA into L3 cache and use/overwrite it before it gets it's turn at the write-back part of the DRAM memory controller.