Re: your mail

Stefan Hajnoczi
2019-03-21T16:13:58Z

[-- Attachment #1: Type: text/plain, Size: 2018 bytes --]

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?

Stefan

[-- Attachment #2: signature.asc --]
[-- Type: application/pgp-signature, Size: 455 bytes --]