On 5/8/2023 6:16 PM, Honnappa Nagarahalli wrote:
> <snip>
>
>>>>
>>>> On 4/21/2023 3:54 PM, Nipun Gupta wrote:
>>>>> Adding support for AMD CDX devices
>>>>>
>>>>> Signed-off-by: Nipun Gupta <nipun.gu...@amd.com>
>>>>> ---
>>>>> config/arm/arm64_cdx_linux_gcc | 17 +++++++++++++++++
>>>>> config/arm/meson.build | 14 ++++++++++++++
>>>>> 2 files changed, 31 insertions(+)
>>>>> create mode 100644 config/arm/arm64_cdx_linux_gcc
>>>>>
>>>>> diff --git a/config/arm/arm64_cdx_linux_gcc
>>>> b/config/arm/arm64_cdx_linux_gcc
>>>>> new file mode 100644
>>>>> index 0000000000..8e6d619dae
>>>>> --- /dev/null
>>>>> +++ b/config/arm/arm64_cdx_linux_gcc
>>>>> @@ -0,0 +1,17 @@
>>>>> +[binaries]
>>>>> +c = ['ccache', 'aarch64-linux-gnu-gcc'] cpp = ['ccache',
>>>>> +'aarch64-linux-gnu-g++'] ar = 'aarch64-linux-gnu-ar'
>>>>> +as = 'aarch64-linux-gnu-as'
>>>>> +strip = 'aarch64-linux-gnu-strip'
>>>>> +pkgconfig = 'aarch64-linux-gnu-pkg-config'
>>>>> +pcap-config = ''
>>>>> +
>>>>> +[host_machine]
>>>>> +system = 'linux'
>>>>> +cpu_family = 'aarch64'
>>>>> +cpu = 'armv8-a'
>>>>> +endian = 'little'
>>>>> +
>>>>> +[properties]
>>>>> +platform = 'cdx'
>>>>> diff --git a/config/arm/meson.build b/config/arm/meson.build index
>>>>> 5213434ca4..39b8929534 100644
>>>>> --- a/config/arm/meson.build
>>>>> +++ b/config/arm/meson.build
>>>>> @@ -305,6 +305,18 @@ soc_bluefield = {
>>>>> 'numa': false
>>>>> }
>>>>>
>>>>> +soc_cdx = {
>>>>> + 'description': 'AMD CDX',
>>>>> + 'implementer': '0x41',
>>>>> + 'part_number': '0xd42',
>>>>> + 'flags': [
>>>>> + ['RTE_MACHINE', '"cdx"'],
>>>>> + ['RTE_MAX_LCORE', 16],
>>>>> + ['RTE_MAX_NUMA_NODES', 1]
>>>>> + ],
>>>>> + 'numa': false
>>>>> +}
>>>>
>>>> Hi Nipun,
>>>>
>>>> Why we need a new arm platform/config? Is it because of above flags?
>>>> If it can work with default values, I think we can drop this patch.
>>>
>>> Hi Ferruh,
>>>
>>> CDX driver works with generic ARM compilation too
>> (arm64_armv8_linux_gcc).
>>>
>>> The versal platforms supporting CDX have A78 cores, and adding this
>>> cdx config Helps to provide gcc option "march= armv8.4-a" which is for
>>> implementer "0xd42" (ARM cortex A78 cores)., whereas for generic ARM
>>> compilation "march= armv8-a".
>>>
>>> Maybe ARM guys can provide more information regarding if there is any
>>> impact on using generic architecture flag (i.e. march= armv8a) on A78 cores.
>>>
>>
>> Hi Honnappa, Ruifeng,
>>
>> Can you please support on this question, what is the difference of 'march=
>> armv8-a' flag (comparing march= armv8a)?
> I am assuming you meant, 'march=armv8.4-a' vs 'march=armv8-a'.
>
Yes
> 'march=armv8-a' will compile for the ARM V8.0-a ISA which is the base V8-a
> version of the ISA. This compilation ensures that the binaries can run on any
> ARM V8-a platforms.
> 'march=armv8.4-a' will compile the binary for ARM V8.4 ISA. The binary will
> use additional (possibly instructions that improve performance) instructions
> which are not supported in ARM V8.0-a. This binary can run only on machines
> that support V8.4-a and higher. But, it will provide optimized binary for the
> target platform.
>
>> Should we consider adding an arm config file to support this flag?
> We support the optimized binary through the config files. We should keep
> these config changes.
>
Got it, thanks for the guidance.
