Re: [dpdk-dev] [PATCH v7 2/4] meson: add infra to support machine specific flags

[Pavan Nikhilesh Bhagavatula <pbhagavatula@marvell.com>]

>-----Original Message-----
>From: Yongseok Koh <yskoh@mellanox.com>
>Sent: Wednesday, April 10, 2019 7:45 AM
>To: jerinjacobk@gmail.com; Pavan Nikhilesh Bhagavatula
><pbhagavatula@marvell.com>
>Cc: Thomas Monjalon <thomas@monjalon.net>; dev <dev@dpdk.org>; Jerin
>Jacob Kollanukkaran <jerinj@marvell.com>
>Subject: [EXT] Re: [dpdk-dev] [PATCH v7 2/4] meson: add infra to support
>machine specific flags
>
>External Email
>
>----------------------------------------------------------------------
>
>> On Apr 9, 2019, at 5:40 PM, Yongseok Koh <yskoh@mellanox.com> wrote:
>>
>>>
>>> On Apr 6, 2019, at 7:27 AM, jerinjacobk@gmail.com wrote:
>>>
>>> From: Pavan Nikhilesh <pbhagavatula@marvell.com>
>>>
>>> Currently, RTE_* flags are set based on the implementer ID but there
>>> might be some micro arch specific differences from the same vendor
>>> eg. CACHE_LINESIZE. Add support to set micro arch specific flags.
>>>
>>> Signed-off-by: Pavan Nikhilesh <pbhagavatula@marvell.com>
>>> Signed-off-by: Jerin Jacob <jerinj@marvell.com>
>>> ---
>>> config/arm/meson.build | 37 ++++++++++++++++++++++++++++++++-----
>>> 1 file changed, 32 insertions(+), 5 deletions(-)
>>>
>>> diff --git a/config/arm/meson.build b/config/arm/meson.build index
>>> 170a4981a..8de3f3e3a 100644
>>> --- a/config/arm/meson.build
>>> +++ b/config/arm/meson.build
>>> @@ -52,12 +52,10 @@ flags_generic = [
>>> 	['RTE_USE_C11_MEM_MODEL', true],
>>> 	['RTE_CACHE_LINE_SIZE', 128]]
>>> flags_cavium = [
>>> -	['RTE_MACHINE', '"thunderx"'],
>>> 	['RTE_CACHE_LINE_SIZE', 128],
>>> 	['RTE_MAX_NUMA_NODES', 2],
>>> 	['RTE_MAX_LCORE', 96],
>>> -	['RTE_MAX_VFIO_GROUPS', 128],
>>> -	['RTE_USE_C11_MEM_MODEL', false]]
>>> +	['RTE_MAX_VFIO_GROUPS', 128]]
>>> flags_dpaa = [
>>> 	['RTE_MACHINE', '"dpaa"'],
>>> 	['RTE_USE_C11_MEM_MODEL', true],
>>> @@ -71,6 +69,27 @@ flags_dpaa2 = [
>>> 	['RTE_MAX_NUMA_NODES', 1],
>>> 	['RTE_MAX_LCORE', 16],
>>> 	['RTE_LIBRTE_DPAA2_USE_PHYS_IOVA', false]]
>>> +flags_default_extra = []
>>> +flags_thunderx_extra = [
>>> +	['RTE_MACHINE', '"thunderx"'],
>>> +	['RTE_USE_C11_MEM_MODEL', false]]
>>> +
>>> +machine_args_generic = [
>>> +	['default', ['-march=armv8-a+crc+crypto']],
>>> +	['native', ['-march=native']],
>>> +	['0xd03', ['-mcpu=cortex-a53']],
>>> +	['0xd04', ['-mcpu=cortex-a35']],
>>> +	['0xd07', ['-mcpu=cortex-a57']],
>>> +	['0xd08', ['-mcpu=cortex-a72']],
>>> +	['0xd09', ['-mcpu=cortex-a73']],
>>> +	['0xd0a', ['-mcpu=cortex-a75']]]
>>> +
>>> +machine_args_cavium = [
>>> +	['default', ['-march=armv8-a+crc+crypto','-mcpu=thunderx']],
>>> +	['native', ['-march=native']],
>>> +	['0xa1', ['-mcpu=thunderxt88'], flags_thunderx_extra],
>>> +	['0xa2', ['-mcpu=thunderxt81'], flags_thunderx_extra],
>>> +	['0xa3', ['-mcpu=thunderxt83'], flags_thunderx_extra]]
>>
>> Looks like there's a mistake in rebasing it?

Seems so will send out v8.

>> You should've removed machine_args_generic and machine_args_cavium in
>> the beginning of this file.
>>
>> Other than that, it looks good to me.
>>
>> BTW, thanks for the patch. I raised this issue before and I was
>> supposed to make the change but you have taken it.
>>
>> Yongseok
>>
>>> ## Arm implementer ID (ARM DDI 0487C.a, Section G7.2.106, Page
>>> G7-5321) impl_generic = ['Generic armv8', flags_generic,
>>> machine_args_generic] @@ -157,8 +176,16 @@ else
>>> 	endif
>>> 	foreach marg: machine[2]
>>> 		if marg[0] == impl_pn
>>> -			foreach f: marg[1]
>>> -				machine_args += f
>>> +			foreach flag: marg[1]
>>> +				if cc.has_argument(flag)
>>> +					machine_args += flag
>>> +				endif
>>> +			endforeach
>>> +			# Apply any extra machine specific flags.
>>> +			foreach flag: marg.get(2, flags_default_extra)
>>> +				if flag.length() > 0
>>> +					dpdk_conf.set(flag[0], flag[1])
>>> +				endif
>
>And setting the extra flags doesn't work well with gcc < 7 because of the
>following,

Extra flags aren't set in this case  as the third variable in the list is missing when 'native' or 'default' is selected
generic= 
        ['default', ['-march=armv8-a+crc+crypto']],
        ['native', ['-march=native']]
cavium=
        ['default', ['-march=armv8-a+crc+crypto','-mcpu=thunderx']],
        ['native', ['-march=native']]

And marg.get falls back to flags_default_extra = [].

>
>        # Primary part number based mcpu flags are supported
>        # for gcc versions > 7
>        if cc.version().version_compare(
>                        '<7.0') or cmd_output.length() == 0
>                if not meson.is_cross_build() and arm_force_native_march == true
>                        impl_pn = 'native'
>                else
>                        impl_pn = 'default'
>                endif
>        endif
>
>Thanks,
>Yongseok
>
>>> 			endforeach
>>> 		endif
>>> 	endforeach
>>> --
>>> 2.21.0