On 8/31/22 6:26 PM, Chautru, Nicolas wrote:
Hi Tom,

-----Original Message-----
From: Tom Rix <t...@redhat.com>
Sent: Wednesday, August 31, 2022 5:28 PM
To: Chautru, Nicolas <nicolas.chau...@intel.com>; Maxime Coquelin
<maxime.coque...@redhat.com>; dev@dpdk.org; tho...@monjalon.net;
gak...@marvell.com; hemant.agra...@nxp.com; Vargas, Hernan
<hernan.var...@intel.com>
Cc: m...@ashroe.eu; Richardson, Bruce <bruce.richard...@intel.com>;
david.march...@redhat.com; step...@networkplumber.org
Subject: Re: [PATCH v1 00/10] baseband/acc200


On 8/31/22 3:37 PM, Chautru, Nicolas wrote:
Hi Thomas, Tom,

-----Original Message-----
From: Tom Rix <t...@redhat.com>
Sent: Wednesday, August 31, 2022 12:26 PM
To: Chautru, Nicolas <nicolas.chau...@intel.com>; Maxime Coquelin
<maxime.coque...@redhat.com>; dev@dpdk.org; tho...@monjalon.net;
gak...@marvell.com; hemant.agra...@nxp.com; Vargas, Hernan
<hernan.var...@intel.com>
Cc: m...@ashroe.eu; Richardson, Bruce <bruce.richard...@intel.com>;
david.march...@redhat.com; step...@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.coque...@redhat.com>
Sent: Tuesday, August 30, 2022 12:45 AM
To: Chautru, Nicolas <nicolas.chau...@intel.com>; dev@dpdk.org;
tho...@monjalon.net; gak...@marvell.com; hemant.agra...@nxp.com;
t...@redhat.com; Vargas, Hernan <hernan.var...@intel.com>
Cc: m...@ashroe.eu; Richardson, Bruce <bruce.richard...@intel.com>;
david.march...@redhat.com; step...@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 ?

These are 2 different HW aspects. The base toplevel configuration registers are 
kept similar on purpose but the underlying IP are totally different design and 
implementation.
Even the registers have differences but not visible here, the actual RDL file 
would define more specifically these registers bitfields and implementation 
including which ones are not implemented (but that is proprietary information), 
and at bbdev level the interface is not some much register based than 
processing based on data from DMA.
Basically even if there was a common driver, all these would be duplicated and 
they are indeed different IP (including different vendors)..
But I agree with the general intent and to have a common driver for the 
integrated driver serie (ACC200, ACC300...) now that we are moving away from 
PCIe/DDR lookaside acceleration and eASIC/FPGA implementation (ACC100/AC101).

Looking a little deeper, at how the driver is lays out some of its bitfields and private data by reviewing the

./acc200/acc200_pmd.h consists for 92 % of ./acc100/rte_acc100_pmd.h

There are some minor changes to existing reserved bitfields.
A new structure for fft.
The acc200_device, the private data for the driver, is an exact copy of 
acc100_device.

acc200_pmd.h is the superset and could be used with little changes as a common 
acc_pmd.h.
acc200 is doing everything the acc100 did in a very similar if not exact way, 
adding the fft feature.

Can you point to some portion of this patchset that is so unique that it could 
not be abstracted to an if-check or function and so requiring this separate, 
nearly identical driver ?

Tom

Tom



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