RE: [RFC PATCH v12 01/17] dlb: add skeleton for DLB driver

[Chen, Mike Ximing]

> -----Original Message-----
> From: Andrew Lunn <andrew@xxxxxxx>
> Sent: Thursday, December 23, 2021 5:23 AM
> To: Chen, Mike Ximing <mike.ximing.chen@xxxxxxxxx>
> Cc: linux-kernel@xxxxxxxxxxxxxxx; arnd@xxxxxxxx; gregkh@xxxxxxxxxxxxxxxxxxx; Williams, Dan J
> <dan.j.williams@xxxxxxxxx>; pierre-louis.bossart@xxxxxxxxxxxxxxx; netdev@xxxxxxxxxxxxxxx;
> davem@xxxxxxxxxxxxx; kuba@xxxxxxxxxx
> Subject: Re: [RFC PATCH v12 01/17] dlb: add skeleton for DLB driver
> 
> On Thu, Dec 23, 2021 at 05:15:34AM +0000, Chen, Mike Ximing wrote:
> >
> >
> > > -----Original Message-----
> > > From: Andrew Lunn <andrew@xxxxxxx>
> > > Sent: Wednesday, December 22, 2021 4:27 PM
> > > To: Chen, Mike Ximing <mike.ximing.chen@xxxxxxxxx>
> > > Cc: linux-kernel@xxxxxxxxxxxxxxx; arnd@xxxxxxxx;
> > > gregkh@xxxxxxxxxxxxxxxxxxx; Williams, Dan J
> > > <dan.j.williams@xxxxxxxxx>; pierre-louis.bossart@xxxxxxxxxxxxxxx;
> > > netdev@xxxxxxxxxxxxxxx; davem@xxxxxxxxxxxxx; kuba@xxxxxxxxxx
> > > Subject: Re: [RFC PATCH v12 01/17] dlb: add skeleton for DLB driver
> > >
> > > > > pointing to skbufs? How are the lifetimes of skbufs managed? How
> > > > > do you get skbufs out of the NIC? Are you using XDP?
> > > >
> > > > This is not a network accelerator in the sense that it does not
> > > > have direct access to the network sockets/ports. We do not use XDP.
> > >
> > > So not using XDP is a problem. I looked at previous versions of this
> > > patch, and it is all DPDK. But DPDK is not in mainline, XDP is. In order for this to be merged into
> mainline you need a mainline user of it.
> > >
> > > Maybe you should abandon mainline, and just get this driver merged into the DPDK fork of Linux?
> > >
> > Hi Andrew,
> >
> > I am not sure why not using XDP is a problem. As mentioned earlier,
> > the DLB driver is not a part of network stack.
> >
> > DPDK is one of applications that can make a good use of DLB, but is
> > not the only one. We have applications that access DLB directly via
> > the kernel driver API without using DPDK.
> 
> Cool. Please can you point at a repo for the code? As i said, we just need a userspace user, which gives us
> a good idea how the hardware is supposed to be used, how the kAPI is to be used, and act as a good test
> case for when kernel modifications are made. But it needs to be pure mainline.
> 
> There have been a few good discussion on LWN about accelerators recently. Worth reading.
> 
We don't have a public repo for dlb yet, but you can download the dlb 
software package at https://www.intel.com/content/www/us/en/download/686372/intel-dynamic-load-balancer.html.
It includes dlb kernel driver and sample user applications (for both
DPDK and non-DPDK users).

I will check out the discussion on LWN.
Thanks for the suggestion.

Mike