Re: [dpdk-dev] vmware vmxnet3-usermap AND DPDK VMXNET3 PMD

["Patel, Rashmin N" <rashmin.n.patel@intel.com>]

I wasn't sure about why anyone would "avoid using UIO just for Virtio even though other devices need uio/vfio in DPDK." I mean I haven't seen anyone using that way and performance wise they both are similar.

But anyways here are the major reasons we had Intel versions:
1. Intel Virtio-PMD version 
	- was elegantly integrated in DPDK code tree and to keep consistency it uses UIO/VFIO framework just like any other PMDs in DPDK/lib 

2. Intel VMXNET3-PMD 
	- does not depend on any other module (i.e. vmxnet3 plugin depends on vmxnet3-usermap.ko module) 	- was elegantly integrated in DPDK code tree and to keep consistency it uses UIO/VFIO framework just like any other PMDs in DPDK/lib
	- is the version VMware contributes today as they think it's a better idea and they would provide ESXi support for that if they need to

Thanks,
Rashmin


-----Original Message-----
From: Thomas Monjalon [mailto:thomas.monjalon@6wind.com] 
Sent: Sunday, November 09, 2014 4:18 PM
To: dev@dpdk.org
Cc: Patel, Rashmin N; Aziz Hajee
Subject: Re: [dpdk-dev] vmware vmxnet3-usermap AND DPDK VMXNET3 PMD

Hi,

2014-11-07 16:53, Patel, Rashmin N:
> Yes, you're right DPDK VMXNET3-PMD in /lib/librte_pmd_vmxnet3 does not 
> support mbuf chaining today. But it's a standalone bsd driver just 
> like any other pmd in that directory, it does not need vmxnet3-usermap.ko module.
> 
> Now there is another vmxnet3 solution in a separate branch as a 
> plugin, which must have vmxnet3-usermap.ko linux module(1), and a user 
> space interface piece(2) to tie it to any DPDK application in the main branch.
> (1) and (2) makes the solution which is known as vmxnet3-plugin. It's 
> been there for a long time just like virtio-plugin, I don't know who 
> uses it, but community can *reply* here if there is still any need of 
> a separate solution that way.

Coming back to last year, 6WIND developped some PMDs for virtio and vmxnet3.
Later, Intel developped their own version using the uio framework.
The versions in the main repository are the Intel ones, whereas the original ones from 6WIND are released as extensions.
For completeness, it must be noted that Brocade worked on their own approach of vmxnet3 and contributed to virtio PMD.
It's now time to merge all these implementations.

The 6WIND implementations show that it's possible to avoid the uio framework.
The virtio-net-pmd use port access granted by iopl().
The vmxnet3-usermap reuse the VMware's kernel module with a special mode for memory mapping. It was a pre-bifurcated logic.

> I'm in favor of consolidating all those version into one elegant 
> solution by grabbing best features from all of them and maintain one 
> copy. I'm sure that developers contributing from VMware would also 
> support that idea because then it makes easy to maintain and debug and 
> bug fix and most importantly avoid such confusion in future.


> -----Original Message-----
> From: dev [mailto:dev-bounces@dpdk.org] On Behalf Of Aziz Hajee
> Sent: Thursday, November 06, 2014 5:47 PM
> To: dev@dpdk.org
> Subject: [dpdk-dev] vmware vmxnet3-usermap AND DPDK VMXNET3 PMD
> 
> I am using the dpdk1.6.0r1
> I could not find a complete clarification, sorry if missed.
> VMXNET3 PMD
> ============
> I have enabled the VMXNET3 PMD  in the dpdk.
>  # Compile burst-oriented VMXNET3 PMD driver  #
> 
> CONFIG_RTE_LIBRTE_VMXNET3_PMD=y
> CONFIG_RTE_LIBRTE_VMXNET3_DEBUG_INIT=y
> CONFIG_RTE_LIBRTE_VMXNET3_DEBUG_RX=n
> CONFIG_RTE_LIBRTE_VMXNET3_DEBUG_TX=n
> CONFIG_RTE_LIBRTE_VMXNET3_DEBUG_TX_FREE=n
> The Intel DPDK VMXNET3 PMD driver does not support mbuf chaining, and I have to set NOMULTSEGS for the vmxnet3 interface init to succeed.
> tx_conf.txq_flags =  ETH_TXQ_FLAGS_NOMULTSEGS Is there a later version 
> of DPDK that supports multiseg for the dpdk
> VMXNET3 PMD.
> 
> vmware vmxnet3-usermap AND  DPDK VMXNET3 PMD 
> =========================================
> Is the vmxnet3-usermap.ko module driver also needed ? (appears that I need, otherwise the eal initialise fails.
> sudo insmod ./vmxnet3-usermap.ko enable_shm=2,2 num_rqs=1,1 
> num_rxds=2048
> num_txds=2048
> 
> I do not understand if VMXNET3 PMD is there, what is the purpose of /vmxnet3-usermap.ko/vmxnet3-usermap.ko ?
> 
> From some responses i saw that the following ifdef RTE_EAL_UNBIND_PORTS is also need to be removed in lib/librte_pmd_vmxnet3/vmxnet3_ethdev.c ?
>      {
>          .name = "rte_vmxnet3_pmd",
>          .id_table = pci_id_vmxnet3_map, -#ifdef RTE_EAL_UNBIND_PORTS
> +// #ifdef RTE_EAL_UNBIND_PORTS
>          .drv_flags = RTE_PCI_DRV_NEED_IGB_UIO, -#endif
> +// #endif
>      },
>      .eth_dev_init = eth_vmxnet3_dev_init,
>      .dev_private_size = sizeof(struct vmxnet3_adapter),
> 
> thanks,
> -aziz