4 ms·
In the first part, the author makes several mistakes including confusing O_DIRECT with DMA. So take this with a grain of salt.
by Vogtinator 9y ago
In the first part, the author makes several mistakes including confusing O_DIRECT with DMA. So take this with a grain of salt.
- ifesdjeen 9y agoIf you could list the mistakes, the author could try making corrections and improve the text. As regard O_DIRECT vs DMA, not sure what exactly you're saying. Understanding Linux Kernel book, for example, is using them quite interchangeably as well (4th edition, 2.6 kernel). Block devices are handled through interrupts and DMA, and these are lower-level means for doing IO. Scylla devs are using it quite interchangeably as well: https://github.com/scylladb/seastar/blob/master/core/reactor.hh#L987-L998 https://github.com/scylladb/seastar/blob/master/core/reactor... Wording might have been not optimal, but author never implied that O_DIRECT is DMA. disclaimer: I'm the author.
- cryptonector 9y agoThe author confused DMA with mmap(). The confusion is in the second part, when referencing the first. Whatever, it's braino.