On 2/7/2023 3:13 PM, jer...@marvell.com wrote:
> From: Jerin Jacob <jer...@marvell.com>
> 

Hi Jerin,

Please find some comments/questions gathered with the help of some
collegues.

> Machine learning inference library
> ==================================
> 
> Definition of machine learning inference
> ----------------------------------------
> Inference in machine learning is the process of making an output prediction
> based on new input data using a pre-trained machine learning model.
> 
> The scope of the RFC would include only inferencing with pre-trained machine 
> learning models,
> training and building/compiling the ML models is out of scope for this RFC or
> DPDK mldev API. Use existing machine learning compiler frameworks for model 
> creation.
> 
> Motivation for the new library
> ------------------------------
> Multiple semiconductor vendors are offering accelerator products such as DPU
> (often called Smart-NIC), FPGA, GPU, etc., which have ML inferencing 
> capabilities
> integrated as part of the product. Use of ML inferencing is increasing in the 
> domain
> of packet processing for flow classification, intrusion, malware and anomaly 
> detection.
> 

Agree on this need.

> Lack of inferencing support through DPDK APIs will involve complexities and
> increased latency from moving data across frameworks (i.e, dataplane to
> non dataplane ML frameworks and vice-versa). Having a standardized DPDK APIs 
> for ML
> inferencing would enable the dataplane solutions to harness the benefit of 
> inline
> inferencing supported by the hardware.
> 

ack

> Contents
> ---------------
> A) API specification for:
> 
> 1) Discovery of ML capabilities (e.g., device specific features) in a vendor
> independent fashion
> 2) Definition of functions to handle ML devices, which includes probing,
> initialization and termination of the devices.
> 3) Definition of functions to handle ML models used to perform inference 
> operations.
> 4) Definition of function to handle quantize and dequantize operations
> 
> B) Common code for above specification
> 
> rfc..v1:
> - Added programmer guide documentation
> - Added implementation for common code
> 
> v2..v1:
> - Moved dynamic log (Stephen)
> - model id to uint16_t from int16t_t (Stephen)
> - added release note updates
> 
> v3..v2:
> - Introduced rte_ml_dev_init() similar to rte_gpu_init() (Stephen, Thomas)
> - In struct rte_ml_dev_data, removed reserved[3] and   __rte_cache_aligned.
> Also, moved name field to the end(Stephen)
>  
> Machine learning library framework
> ----------------------------------
> 
> The ML framework is built on the following model:
> 
> 
>     +-----------------+               rte_ml_[en|de]queue_burst()
>     |                 |                          |
>     |     Machine     o------+     +--------+    |
>     |     Learning    |      |     | queue  |    |    +------+
>     |     Inference   o------+-----o        |<===o===>|Core 0|
>     |     Engine      |      |     | pair 0 |         +------+
>     |                 o----+ |     +--------+
>     |                 |    | |
>     +-----------------+    | |     +--------+
>              ^             | |     | queue  |         +------+
>              |             | +-----o        |<=======>|Core 1|
>              |             |       | pair 1 |         +------+
>              |             |       +--------+
>     +--------+--------+    |
>     | +-------------+ |    |       +--------+
>     | |   Model 0   | |    |       | queue  |         +------+
>     | +-------------+ |    +-------o        |<=======>|Core N|
>     | +-------------+ |            | pair N |         +------+
>     | |   Model 1   | |            +--------+
>     | +-------------+ |
>     | +-------------+ |<------- rte_ml_model_load()
>     | |   Model ..  | |-------> rte_ml_model_info()
>     | +-------------+ |<------- rte_ml_model_start()
>     | +-------------+ |<------- rte_ml_model_stop()
>     | |   Model N   | |<------- rte_ml_model_params_update()
>     | +-------------+ |<------- rte_ml_model_unload()
>     +-----------------+
> 


Should model load/unload, params_update be part of dpdk, or dpdk can
assume these are already in place. For FPGA both options works, what is
the benefit to have these APIs part of DPDK? What are usecases for other
architectures?


Is multiple active models at same time supported?
For FPGA case multiple models may exist at same time, it would be good
to have a way to select the model to use, like a handle for model that
API accepts.
Similarly a handle for model may help chaining models, possibly with
help of additional APIs to define the chaining.

> ML Device: A hardware or software-based implementation of ML device API for
> running inferences using a pre-trained ML model.
> 

Can this device consume multiple queues in parallel?

> ML Model: An ML model is an algorithm trained over a dataset. A model 
> consists of
> procedure/algorithm and data/pattern required to make predictions on live 
> data.
> Once the model is created and trained outside of the DPDK scope, the model 
> can be loaded
> via rte_ml_model_load() and then start it using rte_ml_model_start() API.
> The rte_ml_model_params_update() can be used to update the model parameters 
> such as weight
> and bias without unloading the model using rte_ml_model_unload().
> 
> ML Inference: ML inference is the process of feeding data to the model via
> rte_ml_enqueue_burst() API and use rte_ml_dequeue_burst() API to get the 
> calculated
> outputs/predictions from the started model.
> 
> In all functions of the ML device API, the ML device is designated by an
> integer >= 0 named as device identifier *dev_id*.
> 
> The functions exported by the ML device API to setup a device designated by
> its device identifier must be invoked in the following order:
> 
>      - rte_ml_dev_configure()
>      - rte_ml_dev_queue_pair_setup()
>      - rte_ml_dev_start()
> 
> A model is required to run the inference operations with the user specified 
> inputs.
> Application needs to invoke the ML model API in the following order before 
> queueing
> inference jobs.
> 
>      - rte_ml_model_load()
>      - rte_ml_model_start()
> 
> The rte_ml_model_info() API is provided to retrieve the information related 
> to the model.
> The information would include the shape and type of input and output required 
> for the inference.
> 

It seems there is a sandardization effort for model description, called
ONNX (https://onnx.ai/), supported by many vendors.

Does it make sense that 'rte_ml_model_info()' describes data, and
perhaps model itself too, using onnx format?

> Data quantization and dequantization is one of the main aspects in ML domain. 
> This involves
> conversion of input data from a higher precision to a lower precision data 
> type and vice-versa
> for the output. APIs are provided to enable quantization through 
> rte_ml_io_quantize() and
> dequantization through rte_ml_io_dequantize(). These APIs have the capability 
> to handle input
> and output buffers holding data for multiple batches.
> Two utility APIs rte_ml_io_input_size_get() and rte_ml_io_output_size_get() 
> can used to get the
> size of quantized and de-quantized multi-batch input and output buffers.
> 


It seems quantize and dequantize can be part of model and optimized
during training, can you please some information HW architecture that
needs these APIs?

Does it make sense to have quantize/dequantize as a capability, like in
case HW has specific support for it this can be used, else host can
provide this functionality.

> User can optionally update the model parameters with 
> rte_ml_model_params_update() after
> invoking rte_ml_model_stop() API on a given model ID.
> 
> The application can invoke, in any order, the functions exported by the ML 
> API to enqueue
> inference jobs and dequeue inference response.
> 
> If the application wants to change the device configuration (i.e., call
> rte_ml_dev_configure() or rte_ml_dev_queue_pair_setup()), then application 
> must stop the
> device using rte_ml_dev_stop() API. Likewise, if model parameters need to be 
> updated then
> the application must call rte_ml_model_stop() followed by 
> rte_ml_model_params_update() API
> for the given model. The application does not need to call rte_ml_dev_stop() 
> API for
> any model re-configuration such as rte_ml_model_params_update(), 
> rte_ml_model_unload() etc.
> 
> Once the device is in the start state after invoking rte_ml_dev_start() API 
> and the model is in
> start state after invoking rte_ml_model_start() API, then the application can 
> call
> rte_ml_enqueue() and rte_ml_dequeue() API on the destined device and model ID.
> 
> Finally, an application can close an ML device by invoking the 
> rte_ml_dev_close() function.
> 
> Typical application utilisation of the ML API will follow the following
> programming flow.
> 
> - rte_ml_dev_configure()
> - rte_ml_dev_queue_pair_setup()
> - rte_ml_model_load()
> - rte_ml_model_start()
> - rte_ml_model_info()
> - rte_ml_dev_start()
> - rte_ml_enqueue_burst()
> - rte_ml_dequeue_burst()
> - rte_ml_model_stop()
> - rte_ml_model_unload()
> - rte_ml_dev_stop()
> - rte_ml_dev_close()
> 

is a 'reset()' API needed?

> Regarding multi-threading, by default, all the functions of the ML Device API 
> exported by a PMD
> are lock-free functions which assume to not be invoked in parallel on 
> different logical cores
> on the same target object. For instance, the dequeue function of a poll mode 
> driver cannot be
> invoked in parallel on two logical cores to operate on same queue pair. Of 
> course, this function
> can be invoked in parallel by different logical core on different queue pair.
> It is the responsibility of the user application to enforce this rule.
> 
> Example application usage for ML inferencing
> --------------------------------------------
> This example application is to demonstrate the programming model of ML device
> library. This example omits the error checks to simplify the application. This
> example also assumes that the input data received is quantized and output 
> expected
> is also quantized. In order to handle non-quantized inputs and outputs, users 
> can
> invoke rte_ml_io_quantize() or rte_ml_io_dequantize() for data type 
> conversions.
> 
> #define ML_MODEL_NAME "model"
> #define IO_MZ "io_mz"
> 
> struct app_ctx {
>       char model_file[PATH_MAX];
>       char inp_file[PATH_MAX];
>       char out_file[PATH_MAX];
> 
>       struct rte_ml_model_params params;
>       struct rte_ml_model_info info;
>       uint16_t id;
> 
>       uint64_t input_size;
>       uint64_t output_size;
>       uint8_t *input_buffer;
>       uint8_t *output_buffer;
> } __rte_cache_aligned;
> 
> struct app_ctx ctx;
> 
> static int
> parse_args(int argc, char **argv)
> {
>       int opt, option_index;
>       static struct option lgopts[] = {{"model", required_argument, NULL, 
> 'm'},
>                                        {"input", required_argument, NULL, 
> 'i'},
>                                        {"output", required_argument, NULL, 
> 'o'},
>                                        {NULL, 0, NULL, 0}};
> 
>       while ((opt = getopt_long(argc, argv, "m:i:o:", lgopts, &option_index)) 
> != EOF)
>               switch (opt) {
>               case 'm':
>                       strncpy(ctx.model_file, optarg, PATH_MAX - 1);
>                       break;
>               case 'i':
>                       strncpy(ctx.inp_file, optarg, PATH_MAX - 1);
>                       break;
>               case 'o':
>                       strncpy(ctx.out_file, optarg, PATH_MAX - 1);
>                       break;
>               default:
>                       return -1;
>               }
> 
>       return 0;
> }
> 
> int
> main(int argc, char **argv)
> {
>       struct rte_ml_dev_qp_conf qp_conf;
>       struct rte_ml_dev_config config;
>       struct rte_ml_dev_info dev_info;
>       const struct rte_memzone *mz;
>       struct rte_mempool *op_pool;
>       struct rte_ml_op *op_enq;
>       struct rte_ml_op *op_deq;
> 
>       FILE *fp;
>       int rc;
> 
>       /* Initialize EAL */
>       rc = rte_eal_init(argc, argv);
>       if (rc < 0)
>               rte_exit(EXIT_FAILURE, "Invalid EAL arguments\n");
>       argc -= rc;
>       argv += rc;
> 
>       /* Parse application arguments (after the EAL args) */
>       if (parse_args(argc, argv) < 0)
>               rte_exit(EXIT_FAILURE, "Invalid application arguments\n");
> 
>       /* Step 1: Check for ML devices */
>       if (rte_ml_dev_count() <= 0)
>               rte_exit(EXIT_FAILURE, "Failed to find ML devices\n");
> 
>       /* Step 2: Get device info */
>       if (rte_ml_dev_info_get(0, &dev_info) != 0)
>               rte_exit(EXIT_FAILURE, "Failed to get device info\n");
> 
>       /* Step 3: Configure ML device, use device 0 */
>       config.socket_id = rte_ml_dev_socket_id(0);
>       config.max_nb_models = dev_info.max_models;
>       config.nb_queue_pairs = dev_info.max_queue_pairs;
>       if (rte_ml_dev_configure(0, &config) != 0)
>               rte_exit(EXIT_FAILURE, "Device configuration failed\n");
> 
>       /* Step 4: Setup queue pairs, used qp_id = 0 */
>       qp_conf.nb_desc = 1;
>       if (rte_ml_dev_queue_pair_setup(0, 0, &qp_conf, config.socket_id) != 0)
>               rte_exit(EXIT_FAILURE, "Queue-pair setup failed\n");
> 
>       /* Step 5: Start device */
>       if (rte_ml_dev_start(0) != 0)
>               rte_exit(EXIT_FAILURE, "Device start failed\n");
> 
>       /* Step 6: Read model data and update load params structure */
>       fp = fopen(ctx.model_file, "r+");
>       if (fp == NULL)
>               rte_exit(EXIT_FAILURE, "Failed to open model file\n");
> 
>       fseek(fp, 0, SEEK_END);
>       ctx.params.size = ftell(fp);
>       fseek(fp, 0, SEEK_SET);
> 
>       ctx.params.addr = malloc(ctx.params.size);
>       if (fread(ctx.params.addr, 1, ctx.params.size, fp) != ctx.params.size){
>               fclose(fp);
>               rte_exit(EXIT_FAILURE, "Failed to read model\n");
>       }
>       fclose(fp);
>       strcpy(ctx.params.name, ML_MODEL_NAME);
> 
>       /* Step 7: Load the model */
>       if (rte_ml_model_load(0, &ctx.params, &ctx.id) != 0)
>               rte_exit(EXIT_FAILURE, "Failed to load model\n");
>       free(ctx.params.addr);
> 
>       /* Step 8: Start the model */
>       if (rte_ml_model_start(0, ctx.id) != 0)
>               rte_exit(EXIT_FAILURE, "Failed to start model\n");
> 
>       /* Step 9: Allocate buffers for quantized input and output */
> 
>       /* Get model information */
>       if (rte_ml_model_info_get(0, ctx.id, &ctx.info) != 0)
>               rte_exit(EXIT_FAILURE, "Failed to get model info\n");
> 
>       /* Get the buffer size for input and output */
>       rte_ml_io_input_size_get(0, ctx.id, ctx.info.batch_size, 
> &ctx.input_size, NULL);
>       rte_ml_io_output_size_get(0, ctx.id, ctx.info.batch_size, 
> &ctx.output_size, NULL);
> 
>       mz = rte_memzone_reserve(IO_MZ, ctx.input_size + ctx.output_size, 
> config.socket_id, 0);
>       if (mz == NULL)
>               rte_exit(EXIT_FAILURE, "Failed to create IO memzone\n");
> 
>       ctx.input_buffer = mz->addr;
>       ctx.output_buffer = ctx.input_buffer + ctx.input_size;
> 
>       /* Step 10: Fill the input data */
>       fp = fopen(ctx.inp_file, "r+");
>       if (fp == NULL)
>               rte_exit(EXIT_FAILURE, "Failed to open input file\n");
> 
>       if (fread(ctx.input_buffer, 1, ctx.input_size, fp) != ctx.input_size) {
>               fclose(fp);
>               rte_exit(EXIT_FAILURE, "Failed to read input file\n");
>       }
>       fclose(fp);
> 
>       /* Step 11: Create ML op mempool */
>       op_pool = rte_ml_op_pool_create("ml_op_pool", 1, 0, 0, 
> config.socket_id);
>       if (op_pool == NULL)
>               rte_exit(EXIT_FAILURE, "Failed to create op pool\n");
> 
>       /* Step 12: Form an ML op */
>       rte_mempool_get_bulk(op_pool, (void *)op_enq, 1);
>       op_enq->model_id = ctx.id;
>       op_enq->nb_batches = ctx.info.batch_size;
>       op_enq->mempool = op_pool;
>       op_enq->input.addr = ctx.input_buffer;
>       op_enq->input.length = ctx.input_size;
>       op_enq->input.next = NULL;
>       op_enq->output.addr = ctx.output_buffer;
>       op_enq->output.length = ctx.output_size;
>       op_enq->output.next = NULL;
> 
>       /* Step 13: Enqueue jobs */
>       rte_ml_enqueue_burst(0, 0, &op_enq, 1);
> 
>       /* Step 14: Dequeue jobs and release op pool */
>       while (rte_ml_dequeue_burst(0, 0, &op_deq, 1) != 1)
>               ;
> 
>       /* Step 15: Write output */
>       fp = fopen(ctx.out_file, "w+");
>       if (fp == NULL)
>               rte_exit(EXIT_FAILURE, "Failed to open output file\n");
>       fwrite(ctx.output_buffer, 1, ctx.output_size, fp);
>       fclose(fp);
> 
>       /* Step 16: Clean up */
>       /* Stop ML model */
>       rte_ml_model_stop(0, ctx.id);
>       /* Unload ML model */
>       rte_ml_model_unload(0, ctx.id);
>       /* Free input/output memory */
>       rte_memzone_free(rte_memzone_lookup(IO_MZ));
>       /* Free the ml op back to pool */
>       rte_mempool_put_bulk(op_pool, (void *)op_deq, 1);
>       /* Free ml op pool */
>       rte_mempool_free(op_pool);
>       /* Stop the device */
>       rte_ml_dev_stop(0);
>       rte_ml_dev_close(0);
>       rte_eal_cleanup();
> 
>       return 0;
> }
> 
> 
> Jerin Jacob (1):
>   mldev: introduce machine learning device library
> 
> Srikanth Yalavarthi (11):
>   mldev: support PMD functions for ML device
>   mldev: support ML device handling functions
>   mldev: support ML device queue-pair setup
>   mldev: support handling ML models
>   mldev: support input and output data handling
>   mldev: support ML op pool and ops
>   mldev: support inference enqueue and dequeue
>   mldev: support device statistics
>   mldev: support device extended statistics
>   mldev: support to retrieve error information
>   mldev: support to get debug info and test device
> 
>  MAINTAINERS                              |    5 +
>  doc/api/doxy-api-index.md                |    1 +
>  doc/api/doxy-api.conf.in                 |    1 +
>  doc/guides/prog_guide/img/mldev_flow.svg |  714 ++++++++++++++
>  doc/guides/prog_guide/index.rst          |    1 +
>  doc/guides/prog_guide/mldev.rst          |  186 ++++
>  doc/guides/rel_notes/release_23_03.rst   |    5 +
>  lib/meson.build                          |    1 +
>  lib/mldev/meson.build                    |   27 +
>  lib/mldev/rte_mldev.c                    |  947 ++++++++++++++++++
>  lib/mldev/rte_mldev.h                    | 1119 ++++++++++++++++++++++
>  lib/mldev/rte_mldev_core.h               |  717 ++++++++++++++
>  lib/mldev/rte_mldev_pmd.c                |   62 ++
>  lib/mldev/rte_mldev_pmd.h                |  151 +++
>  lib/mldev/version.map                    |   51 +
>  15 files changed, 3988 insertions(+)
>  create mode 100644 doc/guides/prog_guide/img/mldev_flow.svg
>  create mode 100644 doc/guides/prog_guide/mldev.rst
>  create mode 100644 lib/mldev/meson.build
>  create mode 100644 lib/mldev/rte_mldev.c
>  create mode 100644 lib/mldev/rte_mldev.h
>  create mode 100644 lib/mldev/rte_mldev_core.h
>  create mode 100644 lib/mldev/rte_mldev_pmd.c
>  create mode 100644 lib/mldev/rte_mldev_pmd.h
>  create mode 100644 lib/mldev/version.map
> 

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