Re: [dpdk-dev] Testing memnic for VM to VM transfer

[Hiroshi Shimamoto <h-shimamoto@ct.jp.nec.com>]

Hi,

> Subject: ##freemail## RE: ##freemail## RE: [dpdk-dev] Testing memnic for VM to VM transfer
> 
> Hi, Hiroshi
> 
>    Do you mean I must use DPDK vSwitch in host when I use MEMNIC PMD in
> guest VM? actually, I just want a channel which can put the data from host
> to guest quickly. Do you have any idea that how to write a host application
> to put the data to guest memnic PMD?

Yes, basically I made the MEMNIC interface work with DPDK vSwitch.

By the way, you can mmap() the shm which specified as the ivshmem and put
the proper data to send a packet to guest PMD.
I don't have time to make proper code, but can advise you;
please see common/memnic.h and the memory layout.
1) Set magic and version in header on host.
2) Initialize PMD on guest.
3) Check the reset is 1 and set valid to 1, reset to 0 on host.
4) Use uplink area the default block size 4K.
   Set len and fill ether frame data, then set the status to 2 on host.
   Guest PMD may receive the packet.
   Proceed to the next packet block.

thanks,
Hiroshi

> 
> -----Original Message-----
> From: Hiroshi Shimamoto [mailto:h-shimamoto@ct.jp.nec.com]
> Sent: Wednesday, June 18, 2014 7:11 PM
> To: GongJinrong; 'John Joyce (joycej)'; dev@dpdk.org
> Subject: RE: ##freemail## RE: [dpdk-dev] Testing memnic for VM to VM
> transfer
> 
> Hi,
> 
> > Subject: ##freemail## RE: [dpdk-dev] Testing memnic for VM to VM
> > transfer
> >
> > Hi, Hiroshi
> >
> >    I just start to learn DPDK and memnic, in memnic guide, you said
> > "On host, the shared memory must be initialized by an application
> > using memnic", I am not so clear that how to initialize the share
> > memory in host, do you means use posix API or DPDK API to create the
> > share memory?(it seems memnic guest side use rte_mbuf to transfer
> > data), do you have any sample code to demo how to use memnic in host?
> 
> I don't have simple MEMNIC sample to use it on host.
> Could you please try DPDK vSwitch and enables MEMNIC vport?
> DPDK vSwitch must handle packets between physical NIC port and MEMNIC vport
> exposed to guest with dpdk.org memnic driver.
> 
> thanks,
> Hiroshi
> 
> >
> > -----Original Message-----
> > From: dev [mailto:dev-bounces@dpdk.org] On Behalf Of Hiroshi Shimamoto
> > Sent: Wednesday, June 18, 2014 12:02 PM
> > To: John Joyce (joycej); dev@dpdk.org
> > Subject: Re: [dpdk-dev] Testing memnic for VM to VM transfer
> >
> > Hi,
> >
> > > Subject: [dpdk-dev] Testing memnic for VM to VM transfer
> > >
> > > Hi everyone:
> > >         We are interested in testing the performance of the memnic
> > > driver
> > posted at     http://dpdk.org/browse/memnic/refs/.
> > > We want to compare its performance compared to other techniques to
> > > transfer packets between the guest and the kernel, predominately for
> > > VM to
> > VM transfers.
> > >
> > > We have downloaded the memnic components and have got it running in
> > > a
> > guest VM.
> > >
> > > The question we hope this group might be able to help with is what
> > > would be the best way to processes the packets in the kernel to get
> > > a VM
> > to VM transfer.
> >
> > I think there is no kernel code work with MEMNIC.
> > The recommend switching software on the host is Intel DPDK vSwitch
> > hosted on 01.org and github.
> > https://github.com/01org/dpdk-ovs/tree/development
> >
> > Intel DPDK vSwitch runs on userspace not kernel.
> >
> > I introduced this mechanism to DPDK vSwitch and the guest drivers are
> > maintained in dpdk.org.
> >
> > thanks,
> > Hiroshi
> >
> > >
> > > A couple options might be possible
> > >
> > >
> > > 1.       Common shared buffer between two VMs.  With some utility/code
> to
> > switch TX & RX rings between the two VMs.
> > >
> > > VM1 application --- memnic  ---  common shared memory buffer on the
> > > host --- memnic  ---  VM2 application
> > >
> > > 2.       Special purpose Kernel switching module
> > >
> > > VM1 application --- memnic  ---  shared memory VM1  --- Kernel
> > > switching module  --- shared memory VM2  --- memnic  ---
> > > VM2 application
> > >
> > > 3.       Existing Kernel switching module
> > >
> > > VM1 application --- memnic  ---  shared memory VM1  --- existing
> > > Kernel switching module (e.g. OVS/linux Bridge/VETh pair)
> > > --- shared memory VM2  --- memnic  ---  VM2 application
> > >
> > > Can anyone recommend which approach might be best or easiest?   We would
> > like to avoid writing much (or any) kernel code
> > > so if there are already any open source code or test utilities that
> > > provide one of these options or would be a good starting point to
> > > start
> > from,  a pointer would be much appreciated.
> > >
> > > Thanks in advance
> > >
> > >
> > > John Joyce