Re: DPDK compilers and RHEL 7 support

[Kevin Traynor <ktraynor@redhat.com>]

On 27/03/2025 07:55, Morten Brørup wrote:
> + Red Hat tech board members
> 
>> From: Stephen Hemminger [mailto:stephen@networkplumber.org]
>> Sent: Wednesday, 26 March 2025 20.21
>>
>> On Wed, 26 Mar 2025 19:06:58 +0100
>> Morten Brørup <mb@smartsharesystems.com> wrote:
>>
>>>> From: Bruce Richardson [mailto:bruce.richardson@intel.com]
>>>> Sent: Wednesday, 26 March 2025 17.22
>>>>
>>>> On Tue, Mar 25, 2025 at 05:22:15PM +0000, Bruce Richardson wrote:
>>>>> When doing a build for a target that already has the instruction
>> sets
>>>>> for AVX2/AVX512 enabled, skip emitting the AVX compiler flags, or
>> the
>>>>> skylake-avx512 '-march' flags, as they are unnecessary. Instead,
>> when
>>>>> the default flags produce the desired output, just use them
>>>> unmodified.
>>>>>
>>>>> Depends-on: series-34915 ("remove component-specific logic for
>> AVX
>>>> builds")
>>>>>
>>>>> Signed-off-by: Bruce Richardson <bruce.richardson@intel.com>
>>>>> ---
>>>>>
>>>>> This patchset depends on the previous AVX rework. However,
>> sending it
>>>>> separately as a new RFC because it effectively increases the
>> minimum
>>>>> compiler versions needed for x86 builds - from GCC 5 to 6, and
>>>>> Clang 3.6 to 3.9.
>>>>>
>>>>> For now, I've just documented that as an additional note in the
>> GSG
>>>> that
>>>>> these versions are recommended, but it would be simpler if we
>> could
>>>> just
>>>>> set them as the required minimum baseline (at least in the docs).
>>>>>
>>>>> Feedback on these compiler version requirements welcome.
>>>>>
>>>>
>>>> +techboard
>>>>
>>>> Ping for a little bit of feedback for this. Are we ok to bump the
>>>> minimum
>>>> compiler versions as described above, or will I continue with the
>>>> approach
>>>> in this RFC of keeping the minimum and just recommending the higher
>>>> versions for x86 platforms?
>>>>
>>>> For reference GCC 6.1 was released April 2016[1], and, Clang 3.9
>> was
>>>> released Sept 2016[2]
>>>>
>>>> /Bruce
>>>>
>>>> [1] https://gcc.gnu.org/gcc-6/
>>>> [2] https://releases.llvm.org/
>>>
>>> Considering GCC versions shipped with RHEL [3]...
>>> We kind of support RHEL 7, but we already require a newer compiler
>> (GCC 5) than shipped with RHEL 7 (GCC 4.8).
>>> RHEL 8 ships with GCC 8, which was released in May 2018 [4]. Maybe we
>> can jump to GCC 8?
>>>
>>> BTW, we should also apply the same principle I argued [5] should
>> apply for upgrading the Kernel requirements: There should be a need for
>> specific feature or similar - which there is with your patch - and the
>> details should be mentioned in the release notes.
>>>
>>> [3]: https://access.redhat.com/solutions/19458
>>> [4]: https://gcc.gnu.org/gcc-8/
>>> [5]:
>> https://inbox.dpdk.org/dev/CAMEVEZutf4sJ=EQFONw_bJW0tGTWqTbF_Tk_y38qzBL
>> ccco46Q@mail.gmail.com/T/#me7c8f1dbe4331ccf232d43512d6ddb51458c568a
>>>
>>
>> RHEL 7 reached end of life on June 30, 2024.
>> DPDK need no longer support it on future versions.
> 
> CentOS 7 reached EOL June 2024, yes.
> RHEL 7 reached End of Maintenance June 2024, but RHEL 7 Extended Life Cycle Support is available until June 2028 [6].
> 
> Although RHEL 7 not fully EOL, I would consider "End Of Maintenance" sufficiently dead for future DPDK versions not needing to support it.
> If you are running a production system on a distro that's on Extended Life Cycle Support, you shouldn't deploy a new DPDK version - and if you do anyway, it's your own problem, not the DPDK community's problem.
> @Aaron, @Kevin, @Maxime - speak up if you disagree!
> 

+1

Red Hat will not release new RHEL 7 DPDK packages now and there are no
new features/versions of RHEL 7.

I agree if anyone is running RHEL(/CentOS) 7 at this point, they should
not expect that they can just use new versions of DPDK on it without
having to resolve the dependencies themselves.

> 
> [6]: https://www.redhat.com/en/technologies/linux-platforms/enterprise-linux/rhel-7-end-of-maintenance
>