Re: [dpdk-dev] DPDK 20.08 meson build testpmd not detecting all NUMA nodes

[Bruce Richardson <bruce.richardson@intel.com>]

On Fri, Aug 28, 2020 at 11:11:36AM +0000, Juraj Linkeš wrote:
> 
> 
> > -----Original Message----- From: Bruce Richardson
> > <bruce.richardson@intel.com> Sent: Friday, August 28, 2020 12:30 PM To:
> > Juraj Linkeš <juraj.linkes@pantheon.tech> Cc: dev@dpdk.org Subject: Re:
> > [dpdk-dev] DPDK 20.08 meson build testpmd not detecting all NUMA nodes
> > 
> > On Fri, Aug 28, 2020 at 11:20:02AM +0100, Bruce Richardson wrote:
> > > On Fri, Aug 28, 2020 at 09:26:12AM +0000, Juraj Linkeš wrote:
> > > > Hello DPDK devs,
> > > >
> > > > I've meson built (using just meson build && ninja -C build)
> > > > dpdk-20.08
> > (downloaded from the site) on a Taishan arm server and dpdk-testpmd is
> > incorrectly detecting NUMA nodes on the system:
> > > > EAL: Detected 16 lcore(s) EAL: Detected 1 NUMA nodes
> > > >
> > > > lscpu report 4 NUMA nodes: NUMA node0 CPU(s):   0-15 NUMA node1
> > > > CPU(s):   16-31 NUMA node2 CPU(s):   32-47 NUMA node3 CPU(s):
> > > > 48-63
> > > >
> > > > When built with make T=arm64-armv8a-linuxapp-gcc testpmd is
> > > > detecting
> > NUMA nodes correctly:
> > > > EAL: Detected 64 lcore(s) EAL: Detected 4 NUMA nodes
> > > >
> > > > Any idea what's the difference between the builds? I've looked at
> > > > NUMA
> > config options but those seem ok to me:
> > > > grep NUMA arm64-armv8a-linuxapp-gcc/.config
> > > > build/rte_build_config.h
> > > > arm64-armv8a-linuxapp-gcc/.config:CONFIG_RTE_MAX_NUMA_NODES=8
> > > > arm64-armv8a-linuxapp-gcc/.config:# a "type" is a combination of
> > > > page size and NUMA node. total number of memseg
> > > > arm64-armv8a-linuxapp-
> > gcc/.config:CONFIG_RTE_EAL_NUMA_AWARE_HUGEPAGE
> > > > S=y arm64-armv8a-linuxapp-
> > gcc/.config:CONFIG_RTE_LIBRTE_VHOST_NUMA=y
> > > > build/rte_build_config.h:#define RTE_EAL_NUMA_AWARE_HUGEPAGES 1
> > > > build/rte_build_config.h:#define RTE_HAS_LIBNUMA 1
> > > > build/rte_build_config.h:#define RTE_LIBRTE_VHOST_NUMA 1
> > > > build/rte_build_config.h:#define RTE_MAX_NUMA_NODES 4
> > > >
> > > > Any pointers are welcome.
> > > >
> > > What is the max lcores value in your build config? Do you know what
> > > settings are being chosen for your platform in
> > > config/arm/meson.build?
> > >
> > By way of follow-up, the reason to look at the cores is that the number
> > of numa nodes is detected simply by iterating through all the cores
> > discovered and finding out what NUMA node they are on. If only 16 cores
> > are allowed, then only one NUMA node will be found because all cores
> > discovered will report that as their NUMA location.
> > 
> > /Bruce
> 
> Thanks Bruce, RTE_MAX_LCORE is being set only to 16 (line 39 in
> config/arm/meson.build), so that's the cause. Why is this used in native
> builds? Shouldn't this be discovered?
> 
> I any case, setting it statically for implementer 0x41 seems wrong, as
> there's a big variety different processors under it:
> https://github.com/bp0/armids/blob/master/arm.ids
> 
Sorry, no idea about this, since I don't generally work on/with the
arm/meson.build file. Looking at git, that particular value seems to come
from commit d97108a33231 ("config: change defaults of armv8"), so perhaps
check with the author and reviewer of that patch. [Adding them on CC]

Regards,
/Bruce