Re: [dpdk-dev] IGB_UIO port unbinding

[Stephen Hemminger <stephen@networkplumber.org>]

On Thu, 10 Apr 2014 09:39:35 +0000
"Burakov, Anatoly" <anatoly.burakov@intel.com> wrote:

> Hi everyone
> 
> As you may or may not know, the CONFIG_RTE_EAL_UNBIND_PORTS was deprecated in the official Intel(r) DPDK 1.6.0 release package. However, the code itself (e.g. in lib/librte_eal/linuxapp/eal_pci.c and other places) to support that config option was not removed. My question would be, would anyone be opposed to a patch to remove that code entirely? E.g. does anyone use that functionality?
> 
> Best regards,
> Anatoly Burakov
> DPDK SW Engineer

I actually liked the unbind code that was there. It meant that additional logic
did not have to be added to the startup script to do PCI discovery and finding/mapping
devices.

As it is the EAL startup process is a bit of a mess. It assumes that various
bits of information and infrastructure are already in place prior to starting
the DPDK application.

Other silly DPDK environment issues are: why does DPDK have to know the number
of memory channels in the system? How is the end user of an application supposed
to know this? Sure your hacker might but not end user. It is difficult to impossible
to determine this information at runtime. The best I could find is to use DMI decode
to count number of memory banks and guess!

The CPU mask is also something that should "do the right thing" and use all CPU's
unless told otherwise. Having to wrap every DPDK application in a shell script
makes the application more brittle and creates overlapping effort.