On Tue, Oct 27, 2020 at 03:50:46PM +0000, Juraj Linkeš wrote:
>
>
> > -----Original Message-----
> > From: Bruce Richardson <bruce.richard...@intel.com>
> > Sent: Tuesday, October 27, 2020 12:21 PM
> > To: Juraj Linkeš <juraj.lin...@pantheon.tech>
> > Cc: ruifeng.w...@arm.com; honnappa.nagaraha...@arm.com;
> > phil.y...@arm.com; vcchu...@amazon.com; dharmik.thak...@arm.com;
> > jerinjac...@gmail.com; hemant.agra...@nxp.com; dev@dpdk.org
> > Subject: Re: [PATCH v4 3/6] build: optional NUMA and cpu counts detection
> >
> > On Fri, Oct 23, 2020 at 04:48:05PM +0200, 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.lin...@pantheon.tech>
> > > ---
> > > buildtools/get_cpu_count.py | 7 ++++++
> > > buildtools/get_numa_count.py | 22 +++++++++++++++++
> > > buildtools/meson.build | 2 ++
> > > config/meson.build | 48 ++++++++++++++++++++++++++++++++++--
> > > meson_options.txt | 8 +++---
> > > 5 files changed, 81 insertions(+), 6 deletions(-) create mode 100644
> > > buildtools/get_cpu_count.py create mode 100644
> > > buildtools/get_numa_count.py
> > >
> > > diff --git a/buildtools/get_cpu_count.py b/buildtools/get_cpu_count.py
> > > new file mode 100644 index 000000000..386f85f8b
> > > --- /dev/null
> > > +++ b/buildtools/get_cpu_count.py
> > > @@ -0,0 +1,7 @@
> > > +#!/usr/bin/python3
> > > +# SPDX-License-Identifier: BSD-3-Clause # Copyright (c) 2020
> > > +PANTHEON.tech s.r.o.
> > > +
> > > +import os
> > > +
> > > +print(os.cpu_count())
> > > diff --git a/buildtools/get_numa_count.py
> > > b/buildtools/get_numa_count.py new file mode 100644 index
> > > 000000000..f0c49973a
> > > --- /dev/null
> > > +++ b/buildtools/get_numa_count.py
> > > @@ -0,0 +1,22 @@
> > > +#!/usr/bin/python3
> > > +# SPDX-License-Identifier: BSD-3-Clause # Copyright (c) 2020
> > > +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:
> > > + print(subprocess.run(['sysctl', 'vm.ndomains'],
> > > +capture_output=True).stdout)
> >
> > I think you can shorten this, by just calling subprocess.run and not
> > capturing
> > anything, in which case the stdout will be printed as normal.
> >
> > subprocess.run(['sysctl', 'vm.ndomains'])
> >
>
> This will also print out the resulting object (e.g.
> CompletedProcess(args=['ls', '-ls', '/sys/devices/system/node'],
> returncode=0)), but an assignment will take care of that. I'll make the
> change.
>
Not unless you are running interactively in the python3 REPL.
For example:
$ cat test_meminfo.py
#! /usr/bin/env python3
from subprocess import run
run(['cat', '/proc/meminfo'])
$ python3 test_meminfo.py | tail -n 5
Hugepagesize: 2048 kB
Hugetlb: 17825792 kB
DirectMap4k: 1056788 kB
DirectMap2M: 9758720 kB
DirectMap1G: 88080384 kB
$
