Re: [dpdk-dev] [PATCH] mk: Introduce NXP dpaa2 architecture based on armv8-a

[Jianbo Liu <jianbo.liu@linaro.org>]

On 10 May 2016 at 00:17, Jerin Jacob <jerin.jacob@caviumnetworks.com> wrote:
> On Mon, May 09, 2016 at 11:22:15PM +0800, Jianbo Liu wrote:
>> On 9 May 2016 at 20:11, Jerin Jacob <jerin.jacob@caviumnetworks.com> wrote:
>> > On Mon, May 09, 2016 at 07:02:36PM +0800, Jianbo Liu wrote:
>> >> On 9 May 2016 at 17:06, Jerin Jacob <jerin.jacob@caviumnetworks.com> wrote:
>> >> > On Mon, May 09, 2016 at 07:18:22PM +0530, Hemant Agrawal wrote:
>> >> >> This patch introduces dpaa2 machine target to address difference
>> >> >> in cpu parameter, number of core to 8 and no numa support
>> >> >> w.r.t default armv8-a machine
>> >> >>
>> >> >> Signed-off-by: Hemant Agrawal <hemant.agrawal@nxp.com>
>> >> >> ---
>
> Snip
>
>> >> >> +#
>> >> >> +# Compile Environment Abstraction Layer
>> >> >> +#
>> >> >> +CONFIG_RTE_MAX_LCORE=8
>> >> >> +CONFIG_RTE_MAX_NUMA_NODES=1
>> >> >> +CONFIG_RTE_EAL_IGB_UIO=n
>> >> >
>> >> > I think it makes sense to move this option to generic arm64 config
>> >> > as upstream arm64 kernel does not have support for sysfs based PCI mmap
>> >> > resource file,(/sys/bus/pci/devices/B:D:F/resource[_wc]X) need for
>> >> > CONFIG_RTE_EAL_IGB_UIO to work) and use VFIO for all cases.
>> >> >
>> >> > Any objections?
>> >> >
>> >> Is there any conflict to keep both?
>> >
>> > I would like to avoid the case like below in dpdk.org ml.
>> > http://dpdk.org/ml/archives/dev/2016-January/031313.html
>> >
>> So no conflict to enable both.
>
> IMO, Conflict part comes secondary, It does not even work with upstream kernel.
> Why keep the broken configuration? Two main reasons I think it makes
> sense to disable
> - It is broken, I don't think arm64 kernel developers likes non VFIO approach
I don't think DPDK user is kernel developer in most cases. They maybe
like the traditional way.

> now. So mostly likely it will be broken
> - Trying to avoid out of tree patches wherever is possible as
> distribution folks like to work with upstream version.
Agree. But there is possible that people/company maintain their own kernel tree.

>
>> I'd rather keep as it is for armv8a defconfig, becasue it's the base,
>> any change may affect existing user.
> IMO, It makes sense to disable at armv8a defconfig otherwise all armv8
> variants need add CONFIG_RTE_EAL_IGB_UIO=n in all the configs and its
> arch specific issue.
We don't have to do that.
You didn't explictly disable this config in your current
defconfig_arm64-thunderx-linuxapp-gcc, but you know which module to
bind.