Re: [dpdk-dev] [PATCH v8 2/2] config: enable vhost numa awareness by default

[Thomas Monjalon <thomas@monjalon.net>]

27/06/2017 11:41, Hemant Agrawal:
> On 6/27/2017 2:51 PM, Thomas Monjalon wrote:
> > 27/06/2017 11:18, Hemant Agrawal:
> >> On 6/27/2017 2:16 PM, Ilya Maximets wrote:
> >>> It is safe to enable LIBRTE_VHOST_NUMA by default for all
> >>> configurations where libnuma is already a default dependency.
> >>>
> >>> Signed-off-by: Ilya Maximets <i.maximets@samsung.com>
> >>> ---
> >>>  config/common_linuxapp                    | 1 +
> >>>  config/defconfig_arm-armv7a-linuxapp-gcc  | 1 +
> >>>  config/defconfig_arm64-dpaa2-linuxapp-gcc | 1 +
> >>>  3 files changed, 3 insertions(+)
> > [...]
> >>> --- a/config/defconfig_arm64-dpaa2-linuxapp-gcc
> >>> +++ b/config/defconfig_arm64-dpaa2-linuxapp-gcc
> >>> @@ -47,6 +47,7 @@ CONFIG_RTE_PKTMBUF_HEADROOM=256
> >>>
> >>>  # Doesn't support NUMA
> >>>  CONFIG_RTE_EAL_NUMA_AWARE_HUGEPAGES=y
> >>> +CONFIG_RTE_LIBRTE_VHOST_NUMA=n
> >>>
> >>>  #
> >>>  # Compile Support Libraries for DPAA2
> >>>
> >>
> >> -1
> >> It should also be disabled for generic ARM64. This patch is breaking
> >> generic arm64 config tests on our platforms and creating a unnecessary
> >> dependency.
> >
> > What do you mean? Which ARM64 platform is it breaking?
> > We can specifically disable it on more platforms.
> >
> Unlike x86, ARM only represent a core architecture.
> Different platforms can integrate these cores differently in their SoCs.
> The stock ARM v8 cores do not provide support for NUMA in my knowledge.
> Some vendors have modified ARM cores (e.g. Cavium) to support NUMA 
> architecture. However that is not a common phenomena.
> NUMA config should not be default for generic ARM config. It should be 
> enabled only for architecture supporting it.
> 
> So, *arm64-armv8a-linuxapp-gcc* config is being used by several vendors 
> include NXP. e.g. We use this config on several of our low end systems 
> (non-dpaa). Also, we use it when running in VM with virtio interfaces on 
> all of our different platforms (non-dpaa, dpaa1, dpaa2 etc).

We need more opinions from ARM and Cavium.

The general idea in DPDK config is to enable as much feature as we can.
It conflicts with the general availability of NUMA on ARMv8.