On 3/31/21 2:06 AM, Juraj Linkeš wrote:
> Add an option to automatically discover the host's numa and cpu counts
> and use those values for a non cross-build.
> Give users the option to override the per-arch default values or values
> from cross files by specifying them on the command line with -Dmax_lcores
> and -Dmax_numa_nodes.
> 
> Signed-off-by: Juraj Linkeš <juraj.linkes@pantheon.tech>
> Reviewed-by: Honnappa Nagarahalli <honnappa.nagarahalli@arm.com>
> ---
>   MAINTAINERS                  |  2 ++
>   buildtools/get-cpu-count.py  |  7 ++++++
>   buildtools/get-numa-count.py | 22 +++++++++++++++++
>   buildtools/meson.build       |  2 ++
>   config/meson.build           | 47 ++++++++++++++++++++++++++++++++++--
>   config/x86/meson.build       |  2 ++
>   meson_options.txt            |  8 +++---
>   7 files changed, 84 insertions(+), 6 deletions(-)
>   create mode 100644 buildtools/get-cpu-count.py
>   create mode 100644 buildtools/get-numa-count.py
> 
> diff --git a/MAINTAINERS b/MAINTAINERS
> index 0ec5588540..7270f33cf5 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -99,6 +99,8 @@ F: meson_options.txt
>   F: config/
>   F: buildtools/chkincs/
>   F: buildtools/call-sphinx-build.py
> +F: buildtools/get-cpu-count.py
> +F: buildtools/get-numa-count.py
>   F: buildtools/list-dir-globs.py
>   F: buildtools/pkg-config/
>   F: buildtools/symlink-drivers-solibs.sh
> diff --git a/buildtools/get-cpu-count.py b/buildtools/get-cpu-count.py
> new file mode 100644
> index 0000000000..317b32088f
> --- /dev/null
> +++ b/buildtools/get-cpu-count.py
> @@ -0,0 +1,7 @@
> +#!/usr/bin/env python3
> +# SPDX-License-Identifier: BSD-3-Clause
> +# Copyright (c) 2021 PANTHEON.tech s.r.o.
> +
> +import os
> +
> +print(os.cpu_count())

Returns the expected value on a P9 system.

> diff --git a/buildtools/get-numa-count.py b/buildtools/get-numa-count.py
> new file mode 100644
> index 0000000000..77ef2b9f24
> --- /dev/null
> +++ b/buildtools/get-numa-count.py
> @@ -0,0 +1,22 @@
> +#!/usr/bin/env python3
> +# SPDX-License-Identifier: BSD-3-Clause
> +# Copyright (c) 2021 PANTHEON.tech s.r.o.
> +
> +import ctypes
> +import glob
> +import os
> +import subprocess
> +
> +if os.name == 'posix':
> +    if os.path.isdir('/sys/devices/system/node'):
> +        print(len(glob.glob('/sys/devices/system/node/node*')))
> +    else:
> +        subprocess.run(['sysctl', '-n', 'vm.ndomains'])
> +
> +elif os.name == 'nt':
> +    libkernel32 = ctypes.windll.kernel32
> +
> +    count = ctypes.c_ulong()
> +
> +    libkernel32.GetNumaHighestNodeNumber(ctypes.pointer(count))
> +    print(count.value + 1)

Does not return the expected value on my P9 system (NUMA nodes are not 
contiguous).  Got 6, expect to see at least 8 otherwise I can't use 
lcores on NUMA node 8.

$ python3 ./get-numa-count.py
6
$ lscpu
Architecture:        ppc64le
Byte Order:          Little Endian
CPU(s):              128
On-line CPU(s) list: 0-127
Thread(s) per core:  4
Core(s) per socket:  16
Socket(s):           2
NUMA node(s):        6
Model:               2.3 (pvr 004e 1203)
Model name:          POWER9, altivec supported
CPU max MHz:         3800.0000
CPU min MHz:         2300.0000
L1d cache:           32K
L1i cache:           32K
L2 cache:            512K
L3 cache:            10240K
NUMA node0 CPU(s):   0-63
NUMA node8 CPU(s):   64-127
NUMA node252 CPU(s):
NUMA node253 CPU(s):
NUMA node254 CPU(s):
NUMA node255 CPU(s):

See attached ls-node.txt.gz for full directory structure on a P9 system.

Dave