Re: [dpdk-dev] [PATCH] gpudev: introduce memory API

[Ferruh Yigit <ferruh.yigit@intel.com>]

On 6/3/2021 8:47 AM, Jerin Jacob wrote:
> On Thu, Jun 3, 2021 at 2:05 AM Thomas Monjalon <thomas@monjalon.net> wrote:
>>
>> From: Elena Agostini <eagostini@nvidia.com>
>>
>> The new library gpudev is for dealing with GPU from a DPDK application
>> in a vendor-agnostic way.
>>
>> As a first step, the features are focused on memory management.
>> A function allows to allocate memory inside the GPU,
>> while another one allows to use main (CPU) memory from the GPU.
>>
>> The infrastructure is prepared to welcome drivers in drivers/gpu/
>> as the upcoming NVIDIA one, implementing the gpudev API.
>> Other additions planned for next revisions:
>>   - C implementation file
>>   - guide documentation
>>   - unit tests
>>   - integration in testpmd to enable Rx/Tx to/from GPU memory.
>>
>> The next step should focus on GPU processing task control.
>>
>> Signed-off-by: Elena Agostini <eagostini@nvidia.com>
>> Signed-off-by: Thomas Monjalon <thomas@monjalon.net>
>> ---
>>  .gitignore                           |   1 +
>>  MAINTAINERS                          |   6 +
>>  doc/api/doxy-api-index.md            |   1 +
>>  doc/api/doxy-api.conf.in             |   1 +
>>  doc/guides/conf.py                   |   8 ++
>>  doc/guides/gpus/features/default.ini |  13 ++
>>  doc/guides/gpus/index.rst            |  11 ++
>>  doc/guides/gpus/overview.rst         |   7 +
>>  doc/guides/index.rst                 |   1 +
>>  doc/guides/prog_guide/gpu.rst        |   5 +
>>  doc/guides/prog_guide/index.rst      |   1 +
>>  drivers/gpu/meson.build              |   4 +
>>  drivers/meson.build                  |   1 +
>>  lib/gpudev/gpu_driver.h              |  44 +++++++
>>  lib/gpudev/meson.build               |   9 ++
>>  lib/gpudev/rte_gpudev.h              | 183 +++++++++++++++++++++++++++
>>  lib/gpudev/version.map               |  11 ++
>>  lib/meson.build                      |   1 +
>>  18 files changed, 308 insertions(+)
>>  create mode 100644 doc/guides/gpus/features/default.ini
>>  create mode 100644 doc/guides/gpus/index.rst
>>  create mode 100644 doc/guides/gpus/overview.rst
>>  create mode 100644 doc/guides/prog_guide/gpu.rst
>>  create mode 100644 drivers/gpu/meson.build
>>  create mode 100644 lib/gpudev/gpu_driver.h
>>  create mode 100644 lib/gpudev/meson.build
>>  create mode 100644 lib/gpudev/rte_gpudev.h
>>  create mode 100644 lib/gpudev/version.map
>>
>> diff --git a/.gitignore b/.gitignore
>> index b19c0717e6..49494e0c6c 100644
>> --- a/.gitignore
>> +++ b/.gitignore
>> @@ -14,6 +14,7 @@ doc/guides/compressdevs/overview_feature_table.txt
>>  doc/guides/regexdevs/overview_feature_table.txt
>>  doc/guides/vdpadevs/overview_feature_table.txt
>>  doc/guides/bbdevs/overview_feature_table.txt
>> +doc/guides/gpus/overview_feature_table.txt
>>
>>  # ignore generated ctags/cscope files
>>  cscope.out.po
>> diff --git a/MAINTAINERS b/MAINTAINERS
>> index 5877a16971..c4755dfe9a 100644
>> --- a/MAINTAINERS
>> +++ b/MAINTAINERS
>> @@ -452,6 +452,12 @@ F: app/test-regex/
>>  F: doc/guides/prog_guide/regexdev.rst
>>  F: doc/guides/regexdevs/features/default.ini
>>
>> +GPU API - EXPERIMENTAL
>> +M: Elena Agostini <eagostini@nvidia.com>
>> +F: lib/gpudev/
>> +F: doc/guides/prog_guide/gpu.rst
>> +F: doc/guides/gpus/features/default.ini
>> +
>>  Eventdev API
>>  M: Jerin Jacob <jerinj@marvell.com>
>>  T: git://dpdk.org/next/dpdk-next-eventdev
>> diff --git a/doc/api/doxy-api-index.md b/doc/api/doxy-api-index.md
>> index 1992107a03..bd10342ca2 100644
>> --- a/doc/api/doxy-api-index.md
>> +++ b/doc/api/doxy-api-index.md
>> @@ -21,6 +21,7 @@ The public API headers are grouped by topics:
>>    [compressdev]        (@ref rte_compressdev.h),
>>    [compress]           (@ref rte_comp.h),
>>    [regexdev]           (@ref rte_regexdev.h),
>> +  [gpudev]             (@ref rte_gpudev.h),
> 
> Since this device does not have a queue etc? Shouldn't make it a
> library like mempool with vendor-defined ops?

+1

Current RFC announces additional memory allocation capabilities, which can suits
better as extension to existing memory related library instead of a new device
abstraction library.

> Any specific reason for making it a device? The reason why I am asking
> this is, as other DPDK devices as symmetry in queue(s), configure,
> start, stop operation etc.
> 
> 
>> +
>> +struct rte_gpu_dev {
>> +       /* Backing device. */
>> +       struct rte_device *device;
> 
> See above?
> 
>> +       /* GPU info structure. */