[dpdk-dev] [PATCH v4 1/6] build: alias default build as generic

Juraj Linkeš juraj.linkes at pantheon.tech
Tue Oct 27 08:46:51 CET 2020



> -----Original Message-----
> From: Honnappa Nagarahalli <Honnappa.Nagarahalli at arm.com>
> Sent: Tuesday, October 27, 2020 4:54 AM
> To: Juraj Linkeš <juraj.linkes at pantheon.tech>; bruce.richardson at intel.com;
> Ruifeng Wang <Ruifeng.Wang at arm.com>; Phil Yang <Phil.Yang at arm.com>;
> vcchunga at amazon.com; Dharmik Thakkar <Dharmik.Thakkar at arm.com>;
> jerinjacobk at gmail.com; hemant.agrawal at nxp.com
> Cc: dev at dpdk.org; nd <nd at arm.com>; Honnappa Nagarahalli
> <Honnappa.Nagarahalli at arm.com>; nd <nd at arm.com>
> Subject: RE: [PATCH v4 1/6] 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 at pantheon.tech>
> > ---
> >  config/arm/meson.build | 31 ++++++++++++++++---------------
> >  config/meson.build     |  6 +++---
> >  2 files changed, 19 insertions(+), 18 deletions(-)
> >
> > diff --git a/config/arm/meson.build b/config/arm/meson.build index
> > b49203fa8..491842cad 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) @@ -87,7 +88,7 @@ flags_octeontx2_extra = [
> >  	['RTE_EAL_IGB_UIO', false],
> >  	['RTE_USE_C11_MEM_MODEL', true]]
> >
> > -machine_args_generic = [
> > +machine_args_default = [
> Is this change required? 'machine_args_generic' aligns much better with
> 'machine == generic' (change in the file config/meson.build below)
> 

I thought a lot about the naming and I went back and forth on this before eventually settling on default instead of generic. My reasons are because machine_args_default doesn't just hold information about the build we're doing when machine='generic', but also non-generic information (and thus generic doesn't that well) and it is also used like you would use a default configuration - for implementers which don't have specific configuration.

In a later patch I renamed the "default" configuration of these machine_args to "generic" which is where the actual generic part of the configuration lies. Maybe I could've done that in this patch. Or maybe move this change to that patch - this seems better, since this change is not really needed for this patch and is more of a refactor.

> >  	['default', ['-march=armv8-a+crc', '-moutline-atomics']],
> >  	['native', ['-march=native']],
> >  	['0xd03', ['-mcpu=cortex-a53']],
> > @@ -113,20 +114,20 @@ machine_args_emag = [
> >  	['native', ['-march=native']]]
> >
> >  ## Arm implementer ID (ARM DDI 0487C.a, Section G7.2.106, Page
> > G7-5321) -impl_generic = ['Generic armv8', flags_generic,
> > machine_args_generic]
> > -impl_0x41 = ['Arm', flags_arm, machine_args_generic]
> > -impl_0x42 = ['Broadcom', flags_generic, machine_args_generic]
> > +impl_generic = ['Generic armv8', flags_generic, machine_args_default]
> > +impl_0x41 = ['Arm', flags_arm, machine_args_default]
> > +impl_0x42 = ['Broadcom', flags_generic, machine_args_default]
> >  impl_0x43 = ['Cavium', flags_cavium, machine_args_cavium]
> > -impl_0x44 = ['DEC', flags_generic, machine_args_generic]
> > -impl_0x49 = ['Infineon', flags_generic, machine_args_generic]
> > -impl_0x4d = ['Motorola', flags_generic, machine_args_generic]
> > -impl_0x4e = ['NVIDIA', flags_generic, machine_args_generic]
> > +impl_0x44 = ['DEC', flags_generic, machine_args_default]
> > +impl_0x49 = ['Infineon', flags_generic, machine_args_default]
> > +impl_0x4d = ['Motorola', flags_generic, machine_args_default]
> > +impl_0x4e = ['NVIDIA', flags_generic, machine_args_default]
> >  impl_0x50 = ['Ampere Computing', flags_emag, machine_args_emag]
> > -impl_0x51 = ['Qualcomm', flags_generic, machine_args_generic]
> > -impl_0x53 = ['Samsung', flags_generic, machine_args_generic]
> > -impl_0x56 = ['Marvell ARMADA', flags_armada, machine_args_generic]
> > -impl_0x69 = ['Intel', flags_generic, machine_args_generic] -impl_dpaa
> > = ['NXP DPAA', flags_dpaa, machine_args_generic]
> > +impl_0x51 = ['Qualcomm', flags_generic, machine_args_default]
> > +impl_0x53 = ['Samsung', flags_generic, machine_args_default]
> > +impl_0x56 = ['Marvell ARMADA', flags_armada, machine_args_default]
> > +impl_0x69 = ['Intel', flags_generic, machine_args_default] impl_dpaa
> > += ['NXP DPAA', flags_dpaa, machine_args_default]
> >
> >  dpdk_conf.set('RTE_ARCH_ARM', 1)
> >  dpdk_conf.set('RTE_FORCE_INTRINSICS', 1) @@ -145,7 +146,7 @@ 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..918ca2dfb 100644
> > --- a/config/meson.build
> > +++ b/config/meson.build
> > @@ -68,13 +68,13 @@ else
> >  	machine = get_option('machine')
> >  endif
> >
> > -# machine type 'default' is special, it defaults to the per arch
> > agreed common
> > +# machine type 'generic' is special, it defaults to the per arch
> > +agreed common
> >  # minimal baseline needed for DPDK.
> >  # 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'
> Nit, may be it is worth mentioning that 'default' is allowed for backward
> compatibility?
> 

Ok, I'll add that.

> > -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 +82,7 @@ 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
> > --
> > 2.20.1



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