Re: [Qemu-devel] VSOCK benchmark and optimizations

[Stefan Hajnoczi]

On Mon, Apr 01, 2019 at 06:32:40PM +0200, Stefano Garzarella wrote:
> Hi Alex,
> I'm sending you some benchmarks and information about VSOCK CCing qemu-devel
> and linux-netdev (maybe this info could be useful for others :))
> 
> One of the VSOCK advantages is the simple configuration: you don't need to set
> up IP addresses for guest/host, and it can be used with the standard POSIX
> socket API. [1]
> 
> I'm currently working on it, so the "optimized" values are still work in
> progress and I'll send the patches upstream (Linux) as soon as possible.
> (I hope in 1 or 2 weeks)
> 
> Optimizations:
> + reducing the number of credit update packets
>   - RX side sent, on every packet received, an empty packet only to inform the
>     TX side about the space in the RX buffer.
> + increase RX buffers size to 64 KB (from 4 KB)
> + merge packets to fill RX buffers
> 
> As benchmark tool I used iperf3 [2] modified with VSOCK support:
> 
>              host -> guest [Gbps]      guest -> host [Gbps]
> pkt_size    before opt.  optimized    before opt.  optimized
>   1K            0.5         1.6           1.4         1.4

This is a "large" small package size.  I think 64 bytes is a common
"small" packet size and is worth benchmarking too.

>   2K            1.1         3.1           2.3         2.5
>   4K            2.0         5.6           4.2         4.4
>   8K            3.2        10.2           7.2         7.5
>   16K           6.4        14.2           9.4        11.3
>   32K           9.8        18.9           9.2        17.8
>   64K          13.8        22.9           8.8        25.0
>   128K         17.6        24.5           7.7        25.7
>   256K         19.0        24.8           8.1        25.6
>   512K         20.8        25.1           8.1        25.4

Nice improvements!

Stefan

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