[HN Gopher] A journey to io_uring, AIO and modern storage devices ___________________________________________________________________ A journey to io_uring, AIO and modern storage devices Author : digikata Score : 70 points Date : 2021-05-24 17:13 UTC (5 hours ago) (HTM) web link (clickhouse.tech) (TXT) w3m dump (clickhouse.tech) | TristanBall wrote: | Everything I've seen say using the no-op scheduler for very low | latency devices is the way to go - particularly for nvme and | optane devices.. interesting that it doesn't seem to be mentioned | here, or in the linked paper? | wtallis wrote: | Recent Linux kernels default to not using an IO scheduler with | devices that support multiple queues, which includes NVMe SSDs | but not SATA (at least through AHCI HBAs). Individual distros | can override the kernel's defaults. However, I'm not sure the | difference between no-op and mq-deadline IO scheduling for SATA | SSDs would be big enough to matter for the purposes of this | article's measurements. | anarazel wrote: | It's a really annoying proxy to determine the default | configuration :(. There's plenty devices with multiple | channels that benefits from the increased merging possible | with a scheduler - particularly around writes, where a lot of | consumer SSDs are weak. And conversely, there's plenty | workloads on single queue devices that are hurt by the | scheduler and some of the other heuristics that trigger for | single queue devices... | infogulch wrote: | Pretty interesting to see this and the other io_uring article on | the front page today, given yesterday's post, | | The Unwritten Contract of Solid State Drives (2017) - | https://dl.acm.org/doi/10.1145/3064176.3064187 - | https://news.ycombinator.com/item?id=27260522 | | I'm pretty sure io_uring didn't exist then, and wonder if the new | kernel interface would change anything about the paper. | gumby wrote: | I like the xkcd-style graphs. Anybody know what package that is? | Twirrim wrote: | It's a little over-the-top for my taste in this article. Would | much rather something a little crisper. | sz4kerto wrote: | https://cran.r-project.org/web/packages/xkcd/vignettes/xkcd-... ___________________________________________________________________ (page generated 2021-05-24 23:00 UTC)