Re: [PATCH v1 00/10] baseband/acc200

[Tom Rix <trix@redhat.com>]

On 8/31/22 3:37 PM, Chautru, Nicolas wrote:
> Hi Thomas, Tom,
>
>> -----Original Message-----
>> From: Tom Rix <trix@redhat.com>
>> Sent: Wednesday, August 31, 2022 12:26 PM
>> To: Chautru, Nicolas <nicolas.chautru@intel.com>; Maxime Coquelin
>> <maxime.coquelin@redhat.com>; dev@dpdk.org; thomas@monjalon.net;
>> gakhil@marvell.com; hemant.agrawal@nxp.com; Vargas, Hernan
>> <hernan.vargas@intel.com>
>> Cc: mdr@ashroe.eu; Richardson, Bruce <bruce.richardson@intel.com>;
>> david.marchand@redhat.com; stephen@networkplumber.org
>> Subject: Re: [PATCH v1 00/10] baseband/acc200
>>
>>
>> On 8/30/22 12:45 PM, Chautru, Nicolas wrote:
>>> Hi Maxime,
>>>
>>>> -----Original Message-----
>>>> From: Maxime Coquelin <maxime.coquelin@redhat.com>
>>>> Sent: Tuesday, August 30, 2022 12:45 AM
>>>> To: Chautru, Nicolas <nicolas.chautru@intel.com>; dev@dpdk.org;
>>>> thomas@monjalon.net; gakhil@marvell.com; hemant.agrawal@nxp.com;
>>>> trix@redhat.com; Vargas, Hernan <hernan.vargas@intel.com>
>>>> Cc: mdr@ashroe.eu; Richardson, Bruce <bruce.richardson@intel.com>;
>>>> david.marchand@redhat.com; stephen@networkplumber.org
>>>> Subject: Re: [PATCH v1 00/10] baseband/acc200
>>>>
>>>> Hi Nicolas,
>>>>
>>>> On 7/12/22 15:48, Maxime Coquelin wrote:
>>>>> Hi Nicolas, Hernan,
>>>>>
>>>>> (Adding Hernan in the recipients list)
>>>>>
>>>>> On 7/8/22 02:01, Nicolas Chautru wrote:
>>>>>> This is targeting 22.11 and includes the PMD for the integrated
>>>>>> accelerator on Intel Xeon SPR-EEC.
>>>>>> There is a dependency on that parallel serie still in-flight which
>>>>>> extends the bbdev api
>>>>>> https://patches.dpdk.org/project/dpdk/list/?series=23894
>>>>>>
>>>>>> I will be offline for a few weeks for the summer break but Hernan
>>>>>> will cover for me during that time if required.
>>>>>>
>>>>>> Thanks
>>>>>> Nic
>>>>>>
>>>>>> Nicolas Chautru (10):
>>>>>>      baseband/acc200: introduce PMD for ACC200
>>>>>>      baseband/acc200: add HW register definitions
>>>>>>      baseband/acc200: add info get function
>>>>>>      baseband/acc200: add queue configuration
>>>>>>      baseband/acc200: add LDPC processing functions
>>>>>>      baseband/acc200: add LTE processing functions
>>>>>>      baseband/acc200: add support for FFT operations
>>>>>>      baseband/acc200: support interrupt
>>>>>>      baseband/acc200: add device status and vf2pf comms
>>>>>>      baseband/acc200: add PF configure companion function
>>>>>>
>>>>>>     MAINTAINERS                              |    3 +
>>>>>>     app/test-bbdev/meson.build               |    3 +
>>>>>>     app/test-bbdev/test_bbdev_perf.c         |   76 +
>>>>>>     doc/guides/bbdevs/acc200.rst             |  244 ++
>>>>>>     doc/guides/bbdevs/index.rst              |    1 +
>>>>>>     drivers/baseband/acc200/acc200_pf_enum.h |  468 +++
>>>>>>     drivers/baseband/acc200/acc200_pmd.h     |  690 ++++
>>>>>>     drivers/baseband/acc200/acc200_vf_enum.h |   89 +
>>>>>>     drivers/baseband/acc200/meson.build      |    8 +
>>>>>>     drivers/baseband/acc200/rte_acc200_cfg.h |  115 +
>>>>>>     drivers/baseband/acc200/rte_acc200_pmd.c | 5403
>>>>>> ++++++++++++++++++++++++++++++
>>>>>>     drivers/baseband/acc200/version.map      |   10 +
>>>>>>     drivers/baseband/meson.build             |    1 +
>>>>>>     13 files changed, 7111 insertions(+)
>>>>>>     create mode 100644 doc/guides/bbdevs/acc200.rst
>>>>>>     create mode 100644 drivers/baseband/acc200/acc200_pf_enum.h
>>>>>>     create mode 100644 drivers/baseband/acc200/acc200_pmd.h
>>>>>>     create mode 100644 drivers/baseband/acc200/acc200_vf_enum.h
>>>>>>     create mode 100644 drivers/baseband/acc200/meson.build
>>>>>>     create mode 100644 drivers/baseband/acc200/rte_acc200_cfg.h
>>>>>>     create mode 100644 drivers/baseband/acc200/rte_acc200_pmd.c
>>>>>>     create mode 100644 drivers/baseband/acc200/version.map
>>>>>>
>>>>> Comparing ACC200 & ACC100 header files, I understand ACC200 is an
>>>>> evolution of the ACC10x family. The FEC bits are really close,
>>>>> ACC200 main addition seems to be FFT acceleration which could be
>>>>> handled in ACC10x driver based on device ID.
>>>>>
>>>>> I think both drivers have to be merged in order to avoid code
>>>>> duplication. That's how other families of devices (e.g. i40e) are
>>>>> handled.
>>>> I haven't seen your reply on this point.
>>>> Do you confirm you are working on a single driver for ACC family in
>>>> order to avoid code duplication?
>>>>
>>> The implementation is based on distinct ACC100 and ACC200 drivers. The 2
>> devices are fundamentally different generation, processes and IP.
>>> MountBryce is an eASIC device over PCIe while ACC200 is an integrated
>> accelerator on Xeon CPU.
>>> The actual implementation are not the same, underlying IP are all distinct
>> even if many of the descriptor format have similarities.
>>> The actual capabilities of the acceleration are different and/or new.
>>> The workaround and silicon errata are also different causing different
>> limitation and implementation in the driver (see the serie with ongoing
>> changes for ACC100 in parallel).
>>> This is fundamentally distinct from ACC101 which was a derivative product
>> from ACC100 and where it made sense to share implementation between
>> ACC100 and ACC101.
>>> So in a nutshell these 2 devices and drivers are 2 different beasts and the
>> intention is to keep them intentionally separate as in the serie.
>>> Let me know if unclear, thanks!
>> Nic,
>>
>> I used a similarity checker to compare acc100 and acc200
>>
>> https://dickgrune.com/Programs/similarity_tester/
>>
>> l=simum.log
>> if [ -f $l ]; then
>>       rm $l
>> fi
>>
>> sim_c -s -R -o$l -R -p -P -a .
>>
>> There results are
>>
>> ./acc200/acc200_pf_enum.h consists for 100 % of ./acc100/acc100_pf_enum.h
>> material ./acc100/acc100_pf_enum.h consists for 98 % of
>> ./acc200/acc200_pf_enum.h material ./acc100/rte_acc100_pmd.h consists for
>> 98 % of ./acc200/acc200_pmd.h material ./acc200/acc200_vf_enum.h consists
>> for 95 % of ./acc100/acc100_pf_enum.h material ./acc200/acc200_pmd.h
>> consists for 92 % of ./acc100/rte_acc100_pmd.h material
>> ./acc200/rte_acc200_cfg.h consists for 92 % of ./acc100/rte_acc100_cfg.h
>> material ./acc100/rte_acc100_pmd.c consists for 87 % of
>> ./acc200/rte_acc200_pmd.c material ./acc100/acc100_vf_enum.h consists for
>> 80 % of ./acc200/acc200_pf_enum.h material ./acc200/rte_acc200_pmd.c
>> consists for 78 % of ./acc100/rte_acc100_pmd.c material
>> ./acc100/rte_acc100_cfg.h consists for 75 % of ./acc200/rte_acc200_cfg.h
>> material
>>
>> Spot checking the first *pf_enum.h at 100%, these are the devices'
>> registers, they are the same.
>>
>> I raised this similarity issue with 100 vs 101.
>>
>> Having multiple copies is difficult to support and should be avoided.
>>
>> For the end user, they should have to use only one driver.
>>
> There are really different IP and do not have the same interface (PCIe/DDR vs integrated) and there is big serie of changes which are specific to ACC100 coming in parallel. Any workaround, optimization would be different.
> I agree that for the coming serie of integrated accelerator we will use a unified driver approach but for that very case that would be quite messy to artificially put them within the same PMD.

How is the IP different when 100% of the registers are the same ?

Tom

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