[v8,01/14] build: alias default build as generic

Message ID 1604649795-27476-2-git-send-email-juraj.linkes@pantheon.tech (mailing list archive)
State Superseded, archived
Delegated to: Thomas Monjalon
Headers
Series Arm build options rework |

Checks

Context Check Description
ci/checkpatch success coding style OK

Commit Message

Juraj Linkeš Nov. 6, 2020, 8:03 a.m. UTC
  The current machine='default' build name is not descriptive. The actual
default build is machine='native'. Add an alternative string which does
the same build and better describes what we're building:
machine='generic'. Leave machine='default' for backwards compatibility.

Signed-off-by: Juraj Linkeš <juraj.linkes@pantheon.tech>
---
 config/arm/meson.build                    | 5 +++--
 config/meson.build                        | 9 +++++----
 doc/guides/prog_guide/build-sdk-meson.rst | 4 ++--
 meson_options.txt                         | 2 +-
 4 files changed, 11 insertions(+), 9 deletions(-)
  

Comments

Honnappa Nagarahalli Nov. 6, 2020, 11:52 p.m. UTC | #1
<snip>

> 
> The current machine='default' build name is not descriptive. The actual
> default build is machine='native'. Add an alternative string which does the
> same build and better describes what we're building:
> machine='generic'. Leave machine='default' for backwards compatibility.
> 
> Signed-off-by: Juraj Linkeš <juraj.linkes@pantheon.tech>
> ---
>  config/arm/meson.build                    | 5 +++--
>  config/meson.build                        | 9 +++++----
>  doc/guides/prog_guide/build-sdk-meson.rst | 4 ++--
>  meson_options.txt                         | 2 +-
>  4 files changed, 11 insertions(+), 9 deletions(-)
> 
> diff --git a/config/arm/meson.build b/config/arm/meson.build index
> 42b4e43c7..d4066ade8 100644
> --- a/config/arm/meson.build
> +++ b/config/arm/meson.build
> @@ -1,12 +1,13 @@
>  # SPDX-License-Identifier: BSD-3-Clause  # Copyright(c) 2017 Intel
> Corporation.
>  # Copyright(c) 2017 Cavium, Inc
> +# Copyright(c) 2020 PANTHEON.tech s.r.o.
> 
>  # for checking defines we need to use the correct compiler flags  march_opt =
> '-march=@0@'.format(machine)
> 
>  arm_force_native_march = false
> -arm_force_default_march = (machine == 'default')
> +arm_force_generic_march = (machine == 'generic')
> 
>  flags_common_default = [
>  	# Accelarate rte_memcpy. Be sure to run unit test
> (memcpy_perf_autotest) @@ -148,7 +149,7 @@ else
>  	cmd_generic = ['generic', '', '', 'default', '']
>  	cmd_output = cmd_generic # Set generic by default
>  	machine_args = [] # Clear previous machine args
> -	if arm_force_default_march and not meson.is_cross_build()
> +	if arm_force_generic_march and not meson.is_cross_build()
>  		machine = impl_generic
>  		impl_pn = 'default'
>  	elif not meson.is_cross_build()
> diff --git a/config/meson.build b/config/meson.build index
> 258b01d06..c7f7aa6e2 100644
> --- a/config/meson.build
> +++ b/config/meson.build
> @@ -68,13 +68,14 @@ else
>  	machine = get_option('machine')
>  endif
> 
> -# machine type 'default' is special, it defaults to the per arch agreed common
> -# minimal baseline needed for DPDK.
> +# machine type 'generic' is special, it defaults to the per arch agreed
> +common # minimal baseline needed for DPDK. Machine type 'default' is
> +also supported # with the same meaning for backwards compatibility.
>  # That might not be the most optimized, but the most portable version while
> # still being able to support the CPU features required for DPDK.
>  # This can be bumped up by the DPDK project, but it can never be an  #
> invariant like 'native'
> -if machine == 'default'
> +if machine == 'default' or machine == 'generic'
>  	if host_machine.cpu_family().startswith('x86')
>  		# matches the old pre-meson build systems default
>  		machine = 'corei7'
> @@ -82,7 +83,7 @@ if machine == 'default'
>  		machine = 'armv7-a'
>  	elif host_machine.cpu_family().startswith('aarch')
>  		# arm64 manages defaults in config/arm/meson.build
> -		machine = 'default'
> +		machine = 'generic'
>  	elif host_machine.cpu_family().startswith('ppc')
>  		machine = 'power8'
>  	endif
> diff --git a/doc/guides/prog_guide/build-sdk-meson.rst
> b/doc/guides/prog_guide/build-sdk-meson.rst
> index 3429e2647..c7e12eedf 100644
> --- a/doc/guides/prog_guide/build-sdk-meson.rst
> +++ b/doc/guides/prog_guide/build-sdk-meson.rst
> @@ -85,7 +85,7 @@ Project-specific options are passed used -
> Doption=value::
> 
>  	meson -Denable_docs=true fullbuild  # build and install docs
> 
> -	meson -Dmachine=default  # use builder-independent baseline -
> march
> +	meson -Dmachine=generic  # use builder-independent baseline -
> march
> 
>  	meson -Ddisable_drivers=event/*,net/tap  # disable tap driver and all
>  					# eventdev PMDs for a smaller build
> @@ -114,7 +114,7 @@ Examples of setting some of the same options using
> meson configure::
>          re-scan from meson.
> 
>  .. note::
> -        machine=default uses a config that works on all supported architectures
> +        machine=generic uses a config that works on all supported
> + architectures
>          regardless of the capabilities of the machine where the build is
> happening.
> 
>  As well as those settings taken from ``meson configure``, other options diff --
> git a/meson_options.txt b/meson_options.txt index 9bf18ab6b..ce23289e3
> 100644
> --- a/meson_options.txt
> +++ b/meson_options.txt
> @@ -23,7 +23,7 @@ option('kernel_dir', type: 'string', value: '',
> option('lib_musdk_dir', type: 'string', value: '',
>  	description: 'path to the MUSDK library installation directory')
> option('machine', type: 'string', value: 'native',
> -	description: 'set the target machine type')
> +	description: 'set the target machine type. Set to generic for a build
> +usable on most machines of the build machine architecture, set to
                        ^^^^ all
> +native to let the compiler choose the best fit for the build machine.')
How about: native to let the compiler choose the attributes of the build machine

Otherwise, it looks good to me.
Reviewed-by: Honnappa Nagarahalli <honnappa.nagarahalli@arm.com>

>  option('max_ethports', type: 'integer', value: 32,
>  	description: 'maximum number of Ethernet devices')
> option('max_lcores', type: 'integer', value: 128,
> --
> 2.20.1
  
Juraj Linkeš Nov. 9, 2020, 12:12 p.m. UTC | #2
> -----Original Message-----
> From: Honnappa Nagarahalli <Honnappa.Nagarahalli@arm.com>
> Sent: Saturday, November 7, 2020 12:53 AM
> To: Juraj Linkeš <juraj.linkes@pantheon.tech>; bruce.richardson@intel.com;
> Ruifeng Wang <Ruifeng.Wang@arm.com>; Phil Yang <Phil.Yang@arm.com>;
> vcchunga@amazon.com; Dharmik Thakkar <Dharmik.Thakkar@arm.com>;
> jerinjacobk@gmail.com; hemant.agrawal@nxp.com; Ajit Khaparde
> (ajit.khaparde@broadcom.com) <ajit.khaparde@broadcom.com>;
> ferruh.yigit@intel.com; aconole@redhat.com
> Cc: dev@dpdk.org; nd <nd@arm.com>; Honnappa Nagarahalli
> <Honnappa.Nagarahalli@arm.com>; nd <nd@arm.com>
> Subject: RE: [PATCH v8 01/14] build: alias default build as generic
> 
> <snip>
> 
> >
> > The current machine='default' build name is not descriptive. The
> > actual default build is machine='native'. Add an alternative string
> > which does the same build and better describes what we're building:
> > machine='generic'. Leave machine='default' for backwards compatibility.
> >
> > Signed-off-by: Juraj Linkeš <juraj.linkes@pantheon.tech>
> > ---
> >  config/arm/meson.build                    | 5 +++--
> >  config/meson.build                        | 9 +++++----
> >  doc/guides/prog_guide/build-sdk-meson.rst | 4 ++--
> >  meson_options.txt                         | 2 +-
> >  4 files changed, 11 insertions(+), 9 deletions(-)
> >
> > diff --git a/config/arm/meson.build b/config/arm/meson.build index
> > 42b4e43c7..d4066ade8 100644
> > --- a/config/arm/meson.build
> > +++ b/config/arm/meson.build
> > @@ -1,12 +1,13 @@
> >  # SPDX-License-Identifier: BSD-3-Clause  # Copyright(c) 2017 Intel
> > Corporation.
> >  # Copyright(c) 2017 Cavium, Inc
> > +# Copyright(c) 2020 PANTHEON.tech s.r.o.
> >
> >  # for checking defines we need to use the correct compiler flags
> > march_opt =
> > '-march=@0@'.format(machine)
> >
> >  arm_force_native_march = false
> > -arm_force_default_march = (machine == 'default')
> > +arm_force_generic_march = (machine == 'generic')
> >
> >  flags_common_default = [
> >  	# Accelarate rte_memcpy. Be sure to run unit test
> > (memcpy_perf_autotest) @@ -148,7 +149,7 @@ else
> >  	cmd_generic = ['generic', '', '', 'default', '']
> >  	cmd_output = cmd_generic # Set generic by default
> >  	machine_args = [] # Clear previous machine args
> > -	if arm_force_default_march and not meson.is_cross_build()
> > +	if arm_force_generic_march and not meson.is_cross_build()
> >  		machine = impl_generic
> >  		impl_pn = 'default'
> >  	elif not meson.is_cross_build()
> > diff --git a/config/meson.build b/config/meson.build index
> > 258b01d06..c7f7aa6e2 100644
> > --- a/config/meson.build
> > +++ b/config/meson.build
> > @@ -68,13 +68,14 @@ else
> >  	machine = get_option('machine')
> >  endif
> >
> > -# machine type 'default' is special, it defaults to the per arch
> > agreed common -# minimal baseline needed for DPDK.
> > +# machine type 'generic' is special, it defaults to the per arch
> > +agreed common # minimal baseline needed for DPDK. Machine type
> > +'default' is also supported # with the same meaning for backwards
> compatibility.
> >  # That might not be the most optimized, but the most portable version
> > while # still being able to support the CPU features required for DPDK.
> >  # This can be bumped up by the DPDK project, but it can never be an
> > # invariant like 'native'
> > -if machine == 'default'
> > +if machine == 'default' or machine == 'generic'
> >  	if host_machine.cpu_family().startswith('x86')
> >  		# matches the old pre-meson build systems default
> >  		machine = 'corei7'
> > @@ -82,7 +83,7 @@ if machine == 'default'
> >  		machine = 'armv7-a'
> >  	elif host_machine.cpu_family().startswith('aarch')
> >  		# arm64 manages defaults in config/arm/meson.build
> > -		machine = 'default'
> > +		machine = 'generic'
> >  	elif host_machine.cpu_family().startswith('ppc')
> >  		machine = 'power8'
> >  	endif
> > diff --git a/doc/guides/prog_guide/build-sdk-meson.rst
> > b/doc/guides/prog_guide/build-sdk-meson.rst
> > index 3429e2647..c7e12eedf 100644
> > --- a/doc/guides/prog_guide/build-sdk-meson.rst
> > +++ b/doc/guides/prog_guide/build-sdk-meson.rst
> > @@ -85,7 +85,7 @@ Project-specific options are passed used -
> > Doption=value::
> >
> >  	meson -Denable_docs=true fullbuild  # build and install docs
> >
> > -	meson -Dmachine=default  # use builder-independent baseline -
> > march
> > +	meson -Dmachine=generic  # use builder-independent baseline -
> > march
> >
> >  	meson -Ddisable_drivers=event/*,net/tap  # disable tap driver and all
> >  					# eventdev PMDs for a smaller build
> @@ -114,7 +114,7 @@ Examples
> > of setting some of the same options using meson configure::
> >          re-scan from meson.
> >
> >  .. note::
> > -        machine=default uses a config that works on all supported architectures
> > +        machine=generic uses a config that works on all supported
> > + architectures
> >          regardless of the capabilities of the machine where the build
> > is happening.
> >
> >  As well as those settings taken from ``meson configure``, other
> > options diff -- git a/meson_options.txt b/meson_options.txt index
> > 9bf18ab6b..ce23289e3
> > 100644
> > --- a/meson_options.txt
> > +++ b/meson_options.txt
> > @@ -23,7 +23,7 @@ option('kernel_dir', type: 'string', value: '',
> > option('lib_musdk_dir', type: 'string', value: '',
> >  	description: 'path to the MUSDK library installation directory')
> > option('machine', type: 'string', value: 'native',
> > -	description: 'set the target machine type')
> > +	description: 'set the target machine type. Set to generic for a
> > +build usable on most machines of the build machine architecture, set
> > +to
>                         ^^^^ all

I don't think we've settled this with Bruce. According to him, the build with "machine=generic" on x86 won't necessarily produce a build usable on all machines, so I went with most machines.

> > +native to let the compiler choose the best fit for the build
> > +machine.')
> How about: native to let the compiler choose the attributes of the build machine
> 

I haven't looked at what the docs before, so now here's what GCC docs say: https://gcc.gnu.org/onlinedocs/gcc-8.4.0/gcc/AArch64-Options.html#AArch64-Options:
The value ‘native’ is available on native AArch64 GNU/Linux and causes the compiler to pick the architecture of the host system.

Best fit is kinda vague and choosing the attibutes is probably not using the right verb (it's always going to use the same subset of attributes of the build machine in question, so it's not really a choice), I like use the attributes more.

So it would be either "use the attributes of the build machine" or "pick the architecture of the build machine" (I've changed host system to build machine to match meson language). Both look fine to be, but I'm always inclined to use wording from documentation, even if it's from one compiler. Which one do you like more?

> Otherwise, it looks good to me.
> Reviewed-by: Honnappa Nagarahalli <honnappa.nagarahalli@arm.com>
> 
> >  option('max_ethports', type: 'integer', value: 32,
> >  	description: 'maximum number of Ethernet devices')
> > option('max_lcores', type: 'integer', value: 128,
> > --
> > 2.20.1
  
Bruce Richardson Nov. 9, 2020, 12:47 p.m. UTC | #3
On Mon, Nov 09, 2020 at 12:12:48PM +0000, Juraj Linkeš wrote:
> 
> 
> > -----Original Message-----
> > From: Honnappa Nagarahalli <Honnappa.Nagarahalli@arm.com>
> > Sent: Saturday, November 7, 2020 12:53 AM
> > To: Juraj Linkeš <juraj.linkes@pantheon.tech>; bruce.richardson@intel.com;
> > Ruifeng Wang <Ruifeng.Wang@arm.com>; Phil Yang <Phil.Yang@arm.com>;
> > vcchunga@amazon.com; Dharmik Thakkar <Dharmik.Thakkar@arm.com>;
> > jerinjacobk@gmail.com; hemant.agrawal@nxp.com; Ajit Khaparde
> > (ajit.khaparde@broadcom.com) <ajit.khaparde@broadcom.com>;
> > ferruh.yigit@intel.com; aconole@redhat.com
> > Cc: dev@dpdk.org; nd <nd@arm.com>; Honnappa Nagarahalli
> > <Honnappa.Nagarahalli@arm.com>; nd <nd@arm.com>
> > Subject: RE: [PATCH v8 01/14] build: alias default build as generic
> > 
> > <snip>
> > 
> > >
> > > The current machine='default' build name is not descriptive. The
> > > actual default build is machine='native'. Add an alternative string
> > > which does the same build and better describes what we're building:
> > > machine='generic'. Leave machine='default' for backwards compatibility.
> > >
> > > Signed-off-by: Juraj Linkeš <juraj.linkes@pantheon.tech>
> > > ---
> > >  config/arm/meson.build                    | 5 +++--
> > >  config/meson.build                        | 9 +++++----
> > >  doc/guides/prog_guide/build-sdk-meson.rst | 4 ++--
> > >  meson_options.txt                         | 2 +-
> > >  4 files changed, 11 insertions(+), 9 deletions(-)
> > >
> > > diff --git a/config/arm/meson.build b/config/arm/meson.build index
> > > 42b4e43c7..d4066ade8 100644
> > > --- a/config/arm/meson.build
> > > +++ b/config/arm/meson.build
> > > @@ -1,12 +1,13 @@
> > >  # SPDX-License-Identifier: BSD-3-Clause  # Copyright(c) 2017 Intel
> > > Corporation.
> > >  # Copyright(c) 2017 Cavium, Inc
> > > +# Copyright(c) 2020 PANTHEON.tech s.r.o.
> > >
> > >  # for checking defines we need to use the correct compiler flags
> > > march_opt =
> > > '-march=@0@'.format(machine)
> > >
> > >  arm_force_native_march = false
> > > -arm_force_default_march = (machine == 'default')
> > > +arm_force_generic_march = (machine == 'generic')
> > >
> > >  flags_common_default = [
> > >  	# Accelarate rte_memcpy. Be sure to run unit test
> > > (memcpy_perf_autotest) @@ -148,7 +149,7 @@ else
> > >  	cmd_generic = ['generic', '', '', 'default', '']
> > >  	cmd_output = cmd_generic # Set generic by default
> > >  	machine_args = [] # Clear previous machine args
> > > -	if arm_force_default_march and not meson.is_cross_build()
> > > +	if arm_force_generic_march and not meson.is_cross_build()
> > >  		machine = impl_generic
> > >  		impl_pn = 'default'
> > >  	elif not meson.is_cross_build()
> > > diff --git a/config/meson.build b/config/meson.build index
> > > 258b01d06..c7f7aa6e2 100644
> > > --- a/config/meson.build
> > > +++ b/config/meson.build
> > > @@ -68,13 +68,14 @@ else
> > >  	machine = get_option('machine')
> > >  endif
> > >
> > > -# machine type 'default' is special, it defaults to the per arch
> > > agreed common -# minimal baseline needed for DPDK.
> > > +# machine type 'generic' is special, it defaults to the per arch
> > > +agreed common # minimal baseline needed for DPDK. Machine type
> > > +'default' is also supported # with the same meaning for backwards
> > compatibility.
> > >  # That might not be the most optimized, but the most portable version
> > > while # still being able to support the CPU features required for DPDK.
> > >  # This can be bumped up by the DPDK project, but it can never be an
> > > # invariant like 'native'
> > > -if machine == 'default'
> > > +if machine == 'default' or machine == 'generic'
> > >  	if host_machine.cpu_family().startswith('x86')
> > >  		# matches the old pre-meson build systems default
> > >  		machine = 'corei7'
> > > @@ -82,7 +83,7 @@ if machine == 'default'
> > >  		machine = 'armv7-a'
> > >  	elif host_machine.cpu_family().startswith('aarch')
> > >  		# arm64 manages defaults in config/arm/meson.build
> > > -		machine = 'default'
> > > +		machine = 'generic'
> > >  	elif host_machine.cpu_family().startswith('ppc')
> > >  		machine = 'power8'
> > >  	endif
> > > diff --git a/doc/guides/prog_guide/build-sdk-meson.rst
> > > b/doc/guides/prog_guide/build-sdk-meson.rst
> > > index 3429e2647..c7e12eedf 100644
> > > --- a/doc/guides/prog_guide/build-sdk-meson.rst
> > > +++ b/doc/guides/prog_guide/build-sdk-meson.rst
> > > @@ -85,7 +85,7 @@ Project-specific options are passed used -
> > > Doption=value::
> > >
> > >  	meson -Denable_docs=true fullbuild  # build and install docs
> > >
> > > -	meson -Dmachine=default  # use builder-independent baseline -
> > > march
> > > +	meson -Dmachine=generic  # use builder-independent baseline -
> > > march
> > >
> > >  	meson -Ddisable_drivers=event/*,net/tap  # disable tap driver and all
> > >  					# eventdev PMDs for a smaller build
> > @@ -114,7 +114,7 @@ Examples
> > > of setting some of the same options using meson configure::
> > >          re-scan from meson.
> > >
> > >  .. note::
> > > -        machine=default uses a config that works on all supported architectures
> > > +        machine=generic uses a config that works on all supported
> > > + architectures
> > >          regardless of the capabilities of the machine where the build
> > > is happening.
> > >
> > >  As well as those settings taken from ``meson configure``, other
> > > options diff -- git a/meson_options.txt b/meson_options.txt index
> > > 9bf18ab6b..ce23289e3
> > > 100644
> > > --- a/meson_options.txt
> > > +++ b/meson_options.txt
> > > @@ -23,7 +23,7 @@ option('kernel_dir', type: 'string', value: '',
> > > option('lib_musdk_dir', type: 'string', value: '',
> > >  	description: 'path to the MUSDK library installation directory')
> > > option('machine', type: 'string', value: 'native',
> > > -	description: 'set the target machine type')
> > > +	description: 'set the target machine type. Set to generic for a
> > > +build usable on most machines of the build machine architecture, set
> > > +to
> >                         ^^^^ all
> 
> I don't think we've settled this with Bruce. According to him, the build with "machine=generic" on x86 won't necessarily produce a build usable on all machines, so I went with most machines.
> 
It will produce a build that works on all supported machines, so I think
"all" is probably ok to use.

/Bruce
  
Honnappa Nagarahalli Nov. 9, 2020, 10:54 p.m. UTC | #4
<snip>

> > >
> > > The current machine='default' build name is not descriptive. The
> > > actual default build is machine='native'. Add an alternative string
> > > which does the same build and better describes what we're building:
> > > machine='generic'. Leave machine='default' for backwards compatibility.
> > >
> > > Signed-off-by: Juraj Linkeš <juraj.linkes@pantheon.tech>
> > > ---
> > >  config/arm/meson.build                    | 5 +++--
> > >  config/meson.build                        | 9 +++++----
> > >  doc/guides/prog_guide/build-sdk-meson.rst | 4 ++--
> > >  meson_options.txt                         | 2 +-
> > >  4 files changed, 11 insertions(+), 9 deletions(-)
> > >
> > > diff --git a/config/arm/meson.build b/config/arm/meson.build index
> > > 42b4e43c7..d4066ade8 100644
> > > --- a/config/arm/meson.build
> > > +++ b/config/arm/meson.build
> > > @@ -1,12 +1,13 @@
> > >  # SPDX-License-Identifier: BSD-3-Clause  # Copyright(c) 2017 Intel
> > > Corporation.
> > >  # Copyright(c) 2017 Cavium, Inc
> > > +# Copyright(c) 2020 PANTHEON.tech s.r.o.
> > >
> > >  # for checking defines we need to use the correct compiler flags
> > > march_opt =
> > > '-march=@0@'.format(machine)
> > >
> > >  arm_force_native_march = false
> > > -arm_force_default_march = (machine == 'default')
> > > +arm_force_generic_march = (machine == 'generic')
> > >
> > >  flags_common_default = [
> > >  	# Accelarate rte_memcpy. Be sure to run unit test
> > > (memcpy_perf_autotest) @@ -148,7 +149,7 @@ else
> > >  	cmd_generic = ['generic', '', '', 'default', '']
> > >  	cmd_output = cmd_generic # Set generic by default
> > >  	machine_args = [] # Clear previous machine args
> > > -	if arm_force_default_march and not meson.is_cross_build()
> > > +	if arm_force_generic_march and not meson.is_cross_build()
> > >  		machine = impl_generic
> > >  		impl_pn = 'default'
> > >  	elif not meson.is_cross_build()
> > > diff --git a/config/meson.build b/config/meson.build index
> > > 258b01d06..c7f7aa6e2 100644
> > > --- a/config/meson.build
> > > +++ b/config/meson.build
> > > @@ -68,13 +68,14 @@ else
> > >  	machine = get_option('machine')
> > >  endif
> > >
> > > -# machine type 'default' is special, it defaults to the per arch
> > > agreed common -# minimal baseline needed for DPDK.
> > > +# machine type 'generic' is special, it defaults to the per arch
> > > +agreed common # minimal baseline needed for DPDK. Machine type
> > > +'default' is also supported # with the same meaning for backwards
> > compatibility.
> > >  # That might not be the most optimized, but the most portable
> > > version while # still being able to support the CPU features required for
> DPDK.
> > >  # This can be bumped up by the DPDK project, but it can never be an
> > > # invariant like 'native'
> > > -if machine == 'default'
> > > +if machine == 'default' or machine == 'generic'
> > >  	if host_machine.cpu_family().startswith('x86')
> > >  		# matches the old pre-meson build systems default
> > >  		machine = 'corei7'
> > > @@ -82,7 +83,7 @@ if machine == 'default'
> > >  		machine = 'armv7-a'
> > >  	elif host_machine.cpu_family().startswith('aarch')
> > >  		# arm64 manages defaults in config/arm/meson.build
> > > -		machine = 'default'
> > > +		machine = 'generic'
> > >  	elif host_machine.cpu_family().startswith('ppc')
> > >  		machine = 'power8'
> > >  	endif
> > > diff --git a/doc/guides/prog_guide/build-sdk-meson.rst
> > > b/doc/guides/prog_guide/build-sdk-meson.rst
> > > index 3429e2647..c7e12eedf 100644
> > > --- a/doc/guides/prog_guide/build-sdk-meson.rst
> > > +++ b/doc/guides/prog_guide/build-sdk-meson.rst
> > > @@ -85,7 +85,7 @@ Project-specific options are passed used -
> > > Doption=value::
> > >
> > >  	meson -Denable_docs=true fullbuild  # build and install docs
> > >
> > > -	meson -Dmachine=default  # use builder-independent baseline -
> > > march
> > > +	meson -Dmachine=generic  # use builder-independent baseline -
> > > march
> > >
> > >  	meson -Ddisable_drivers=event/*,net/tap  # disable tap driver and all
> > >  					# eventdev PMDs for a smaller build
> > @@ -114,7 +114,7 @@ Examples
> > > of setting some of the same options using meson configure::
> > >          re-scan from meson.
> > >
> > >  .. note::
> > > -        machine=default uses a config that works on all supported
> architectures
> > > +        machine=generic uses a config that works on all supported
> > > + architectures
> > >          regardless of the capabilities of the machine where the
> > > build is happening.
> > >
> > >  As well as those settings taken from ``meson configure``, other
> > > options diff -- git a/meson_options.txt b/meson_options.txt index
> > > 9bf18ab6b..ce23289e3
> > > 100644
> > > --- a/meson_options.txt
> > > +++ b/meson_options.txt
> > > @@ -23,7 +23,7 @@ option('kernel_dir', type: 'string', value: '',
> > > option('lib_musdk_dir', type: 'string', value: '',
> > >  	description: 'path to the MUSDK library installation directory')
> > > option('machine', type: 'string', value: 'native',
> > > -	description: 'set the target machine type')
> > > +	description: 'set the target machine type. Set to generic for a
> > > +build usable on most machines of the build machine architecture,
> > > +set to
> >                         ^^^^ all
> 
> I don't think we've settled this with Bruce. According to him, the build with
> "machine=generic" on x86 won't necessarily produce a build usable on all
> machines, so I went with most machines.
> 
> > > +native to let the compiler choose the best fit for the build
> > > +machine.')
> > How about: native to let the compiler choose the attributes of the
> > build machine
> >
> 
> I haven't looked at what the docs before, so now here's what GCC docs say:
> https://gcc.gnu.org/onlinedocs/gcc-8.4.0/gcc/AArch64-
> Options.html#AArch64-Options:
> The value ‘native’ is available on native AArch64 GNU/Linux and causes the
> compiler to pick the architecture of the host system.
> 
> Best fit is kinda vague and choosing the attibutes is probably not using the
> right verb (it's always going to use the same subset of attributes of the build
> machine in question, so it's not really a choice), I like use the attributes more.
> 
> So it would be either "use the attributes of the build machine" or "pick the
> architecture of the build machine" (I've changed host system to build machine
> to match meson language). Both look fine to be, but I'm always inclined to use
> wording from documentation, even if it's from one compiler. Which one do
> you like more?
I am fine with "pick the architecture of the build machine"

> 
> > Otherwise, it looks good to me.
> > Reviewed-by: Honnappa Nagarahalli <honnappa.nagarahalli@arm.com>
> >
> > >  option('max_ethports', type: 'integer', value: 32,
> > >  	description: 'maximum number of Ethernet devices')
> > > option('max_lcores', type: 'integer', value: 128,
> > > --
> > > 2.20.1
  

Patch

diff --git a/config/arm/meson.build b/config/arm/meson.build
index 42b4e43c7..d4066ade8 100644
--- a/config/arm/meson.build
+++ b/config/arm/meson.build
@@ -1,12 +1,13 @@ 
 # SPDX-License-Identifier: BSD-3-Clause
 # Copyright(c) 2017 Intel Corporation.
 # Copyright(c) 2017 Cavium, Inc
+# Copyright(c) 2020 PANTHEON.tech s.r.o.
 
 # for checking defines we need to use the correct compiler flags
 march_opt = '-march=@0@'.format(machine)
 
 arm_force_native_march = false
-arm_force_default_march = (machine == 'default')
+arm_force_generic_march = (machine == 'generic')
 
 flags_common_default = [
 	# Accelarate rte_memcpy. Be sure to run unit test (memcpy_perf_autotest)
@@ -148,7 +149,7 @@  else
 	cmd_generic = ['generic', '', '', 'default', '']
 	cmd_output = cmd_generic # Set generic by default
 	machine_args = [] # Clear previous machine args
-	if arm_force_default_march and not meson.is_cross_build()
+	if arm_force_generic_march and not meson.is_cross_build()
 		machine = impl_generic
 		impl_pn = 'default'
 	elif not meson.is_cross_build()
diff --git a/config/meson.build b/config/meson.build
index 258b01d06..c7f7aa6e2 100644
--- a/config/meson.build
+++ b/config/meson.build
@@ -68,13 +68,14 @@  else
 	machine = get_option('machine')
 endif
 
-# machine type 'default' is special, it defaults to the per arch agreed common
-# minimal baseline needed for DPDK.
+# machine type 'generic' is special, it defaults to the per arch agreed common
+# minimal baseline needed for DPDK. Machine type 'default' is also supported
+# with the same meaning for backwards compatibility.
 # That might not be the most optimized, but the most portable version while
 # still being able to support the CPU features required for DPDK.
 # This can be bumped up by the DPDK project, but it can never be an
 # invariant like 'native'
-if machine == 'default'
+if machine == 'default' or machine == 'generic'
 	if host_machine.cpu_family().startswith('x86')
 		# matches the old pre-meson build systems default
 		machine = 'corei7'
@@ -82,7 +83,7 @@  if machine == 'default'
 		machine = 'armv7-a'
 	elif host_machine.cpu_family().startswith('aarch')
 		# arm64 manages defaults in config/arm/meson.build
-		machine = 'default'
+		machine = 'generic'
 	elif host_machine.cpu_family().startswith('ppc')
 		machine = 'power8'
 	endif
diff --git a/doc/guides/prog_guide/build-sdk-meson.rst b/doc/guides/prog_guide/build-sdk-meson.rst
index 3429e2647..c7e12eedf 100644
--- a/doc/guides/prog_guide/build-sdk-meson.rst
+++ b/doc/guides/prog_guide/build-sdk-meson.rst
@@ -85,7 +85,7 @@  Project-specific options are passed used -Doption=value::
 
 	meson -Denable_docs=true fullbuild  # build and install docs
 
-	meson -Dmachine=default  # use builder-independent baseline -march
+	meson -Dmachine=generic  # use builder-independent baseline -march
 
 	meson -Ddisable_drivers=event/*,net/tap  # disable tap driver and all
 					# eventdev PMDs for a smaller build
@@ -114,7 +114,7 @@  Examples of setting some of the same options using meson configure::
         re-scan from meson.
 
 .. note::
-        machine=default uses a config that works on all supported architectures
+        machine=generic uses a config that works on all supported architectures
         regardless of the capabilities of the machine where the build is happening.
 
 As well as those settings taken from ``meson configure``, other options
diff --git a/meson_options.txt b/meson_options.txt
index 9bf18ab6b..ce23289e3 100644
--- a/meson_options.txt
+++ b/meson_options.txt
@@ -23,7 +23,7 @@  option('kernel_dir', type: 'string', value: '',
 option('lib_musdk_dir', type: 'string', value: '',
 	description: 'path to the MUSDK library installation directory')
 option('machine', type: 'string', value: 'native',
-	description: 'set the target machine type')
+	description: 'set the target machine type. Set to generic for a build usable on most machines of the build machine architecture, set to native to let the compiler choose the best fit for the build machine.')
 option('max_ethports', type: 'integer', value: 32,
 	description: 'maximum number of Ethernet devices')
 option('max_lcores', type: 'integer', value: 128,