Скачать или смотреть Multiqueue in the block layer

Devices like virtio-blk and virtio-scsi have long supported a configurable number of queues, which is supposed to allow improving performance during heavy I/O by processing the queues in parallel. However, while this looks nice and shiny from the guest's perspective, it has been a lie on QEMU's side so far: All the queues are still processed by a single thread and not in parallel because QEMU's block layer wasn't written with thread safety in mind.

In a tale of coroutines, nested event loops, block node draining and locks, Emanuele and Kevin will talk about the challenges in making the block layer thread-safe and ways to resolve these challenges so that QEMU can finally deliver on the promise.