With Linux 4.12, Clouds/VMs Backed By NVMe Storage Should Be Much Faster

[phoronix]

Phoronix: With Linux 4.12, Clouds/VMs Backed By NVMe Storage Should Be Much Faster

With the Linux 4.12 kernel when running in emulated environments like VMs/clouds atop NVMe (NVM Express) solid-state storage you should be able to obtain much greater performance...

http://www.phoronix.com/scan.php?page=news_item&px=NVMe-4.12-Faster-Virtual

[man-walking]

I don't understand why should be faster then VirtIO

[mcloud]

Given their benchmark figures, its 400% faster than without the new path

[helen.fornazier]

It is true that Virtio uses this same "trick" to reduce the number of VM exits, in terms of performance both solutions should be similar. The advantage for having the Doorbell Buffer command in the NVMe official specification is more in a practical point of view. The guest operating system won't need to switch to another driver to make use of the enhanced performance, and also other operating system other then Linux/BSD that don't have Virtio can also benefit if they add support of the Doorbell Buffer command in their existing NVMe driver (which is way simpler then implementing virtio from scratch). Also, a real hardware could implement this new command if it sees any advantage on that, if the hardware have access to the part of the memory where the queues are, it could go and fetch the nvme commands when idle, but this use case haven't being proved afaik