Re: [SPDK] SPDK & DPDK in one process

[Thomas Monjalon <thomas.monjalon at 6wind.com>]

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Hi SPDK

2016-10-24 23:30, Walker, Benjamin:
> On Sat, 2016-10-22 at 21:19 +0300, Gregory Etelson wrote:
> > Hello
> > 
> > I need to run DPDK networking and access NVMe device in the same process.
> > 
> > rte_eal_init() initializes network PMD drivers normally
> > But spdk_nvme_probe() activates network devices probe for the second time and
> > rte exits with error.
> > 
> > To resolve this failure I register NVMe controller driver as DPDK PMD.
> > Now I can pass NVMe device PCI address to EAL initialization with `-w'
> > parameter along with network devices
> > PMD template I use is attached below.
> > 
> > Is there another way to run DPDK and SPDK in the same process ? 
> 
> You found the best way right now, but I'm working with the DPDK community to
> improve here. It seems like the rte_pci module doesn't handle multiple calls to
> rte_eal_pci_probe, which is what SPDK is doing. The most important change to
> DPDK that needs to happen is that rte_eal_pci_probe needs to not call the driver
> initialization function for devices that already have a driver loaded. That's a
> very easy fix that solves your problem and I'll be submitting a patch to the
> DPDK community.
> 
> Longer term I think we really need to work with DPDK to clean up some of these
> PCI interfaces so they're more dynamic and can handle devices and drivers coming
> and going at run time.

Yes you are welcome to contribute to DPDK.

There is a slow work in progress to better design the EAL in order to ease
integration of new buses and allow true hotplugging.
We do these core changes step by step:

After having better designed the device object, we are changing the bus model.
Instead of having PCI the default bus, and vdev an exception, we need a
generic bus object to plug PCI, vdev and other buses in it.
Then we should design a better app event mechanism, usable for hotplug.
Another step could be an auto-binding.
And at the end we could be plugged to hardware events like udev.