On 1/2/16, 1:14 PM, "Stephen Hemminger" <stephen at networkplumber.org> wrote:
>On Sat, 2 Jan 2016 19:52:16 +0100 >Jan Viktorin <viktorin at rehivetech.com> wrote: > >> On Sat, 2 Jan 2016 18:35:08 +0000 >> "Wiles, Keith" <keith.wiles at intel.com> wrote: >> >> > >Yes, DPDK needs to work in embedded environments with device tree. >> > >Would it be possible reimplement device tree parsing in user space? >> > >Ideally with a shared code from kernel?? >> > >> > Stephen, Do you mean we have to add kernel code to support DPDK on SoC >> > Platforms? If that is the case I would like to not require code be added >> > to the kernel to support DPDK. >> >> We will need a kernel module. But this is not necessarily related to the >> device-tree parsing. >> >> > > >> > >On a pratical level, the new SoC support must be optional >> > >(via DPDK config infrastructure), since most architectures won't be using >> > >it. >> > >In most cases, it is better from usability if everything is runtime based, >> > >but with SoC this is a platform/architecture configuration. >> > >> > I am not sure I agree with the optional support, as it could be stated >> > that PCI support is optional on SoC platforms. It would be best to not >> > treat SoC support as special compared to PCI support. Other then extra >> > footprint it does not seem reasonable to require SoC support to be >> > ifdef?ed in the code. Plus adding more ifdefs is not a good testing >> > solution. >> >> This is a matter of preserving ABI. Turning PCI-support to be optional >> seems to be a difficult step at the moment. >> >> > >> > Can we detect somehow we are on a system with SoC support or even a system >> > that supports PCI for that matter? >> >> IMO, we can detect two things: "PCI is present on the system" and >> "Device tree is accessible in /proc/device-tree". Is this acceptable? >> > >I am just as concerned with building and having useless code. >For now most environments can just use PCI, and having to carry around >dead code seems wasteful and potential for some security abuse as well. Hi Stephen, With including every archive with the include whole archive option means we already have a huge amount of dead code in a DPDK image :-( Adding a bit more is not going to make a difference IMO. Also a system without PCI could be a security abuse too. I think we just figure out how not to call the PCI or SoC code at runtime if not supported and compile it in always. > Regards, Keith
