On Thu, 2019-03-21 at 16:13 +0000, Stefan Hajnoczi wrote: > On Tue, Mar 19, 2019 at 04:41:07PM +0200, Maxim Levitsky wrote: > > Date: Tue, 19 Mar 2019 14:45:45 +0200 > > Subject: [PATCH 0/9] RFC: NVME VFIO mediated device > > > > Hi everyone! > > > > In this patch series, I would like to introduce my take on the problem of > > doing > > as fast as possible virtualization of storage with emphasis on low latency. > > > > In this patch series I implemented a kernel vfio based, mediated device > > that > > allows the user to pass through a partition and/or whole namespace to a > > guest. > > > > The idea behind this driver is based on paper you can find at > > https://www.usenix.org/conference/atc18/presentation/peng, > > > > Although note that I stared the development prior to reading this paper, > > independently. > > > > In addition to that implementation is not based on code used in the paper > > as > > I wasn't being able at that time to make the source available to me. > > > > ***Key points about the implementation:*** > > > > * Polling kernel thread is used. The polling is stopped after a > > predefined timeout (1/2 sec by default). > > Support for all interrupt driven mode is planned, and it shows promising > > results. > > > > * Guest sees a standard NVME device - this allows to run guest with > > unmodified drivers, for example windows guests. > > > > * The NVMe device is shared between host and guest. > > That means that even a single namespace can be split between host > > and guest based on different partitions. > > > > * Simple configuration > > > > *** Performance *** > > > > Performance was tested on Intel DC P3700, With Xeon E5-2620 v2 > > and both latency and throughput is very similar to SPDK. > > > > Soon I will test this on a better server and nvme device and provide > > more formal performance numbers. > > > > Latency numbers: > > ~80ms - spdk with fio plugin on the host. > > ~84ms - nvme driver on the host > > ~87ms - mdev-nvme + nvme driver in the guest > > You mentioned the spdk numbers are with vhost-user-nvme. Have you > measured SPDK's vhost-user-blk? I had lot of measuments of vhost-user-blk vs vhost-user-nvme. vhost-user-nvme was always a bit faster but only a bit. Thus I don't think it makes sense to benchamrk against vhost-user-blk. Best regards, Maxim Levitsky
