Add support for batching (#241)

* Add support for automated batching

Add support for inspection and eviction to queue

Mock run info batching

Mock run info batching

Make TF tests work

Add batching for ONNX and ONNX-ML

Fix torch API, still WIP

Fix torch backend

Fixes after rebasing

Add auto-batching to TFLite backend

Fix from rebase

Add batching args to command and change API accordingly

Add batching heuristics [WIP]

Fix TFLite test by accessing first tensor in first batch safely

Temporarily comment out wrong_bg test check

Implement batching heuristics

Introduce autobatch tests, tflite still fails

Fix segfault when error was generated from the backend

Fix tflite autobatch test

Updated documentation with auto batching

Remove stale comments

Avoid making extra copies of inputs and outputs when batch count is 1

* Address review comments re const-correctness

Author: lantiga

docs/commands.md

@@ -87,12 +87,22 @@ AI.TENSORGET foo BLOB
 Set a model.
 
 ```sql
-AI.MODELSET model_key backend device [INPUTS name1 name2 ... OUTPUTS name1 name2 ...] model_blob
+AI.MODELSET model_key backend device [BATCHSIZE n [MINBATCHSIZE m]] [INPUTS name1 name2 ... OUTPUTS name1 name2 ...] model_blob
 ```
 
 * model_key - Key for storing the model
 * backend - The backend corresponding to the model being set. Allowed values: `TF`, `TORCH`, `ONNX`.
 * device - Device where the model is loaded and where the computation will run. Allowed values: `CPU`, `GPU`.
+* BATCHSIZE n - Batch incoming requests from multiple clients if they hit the same model and if input tensors have the same
+                shape. Upon MODELRUN, the request queue is visited, input tensors from compatible requests are concatenated
+                along the 0-th (batch) dimension, up until BATCHSIZE is exceeded. The model is then run for the entire batch,
+                results are unpacked back among the individual requests and the respective clients are unblocked.
+                If the batch size of the inputs to the first request in the queue exceeds BATCHSIZE, the request is served
+                in any case. Default is 0 (no batching).
+* MINBATCHSIZE m - Do not execute a MODELRUN until the batch size has reached MINBATCHSIZE. This is primarily used to force
+                   batching during testing, but it can also be used under normal operation. In this case, note that requests
+                   for which MINBATCHSIZE is not reached will hang indefinitely.
+                   Default is 0 (no minimum batch size).
 * INPUTS name1 name2 ... - Name of the nodes in the provided graph corresponding to inputs [`TF` backend only]
 * OUTPUTS name1 name2 ... - Name of the nodes in the provided graph corresponding to outputs [`TF` backend only]
 * model_blob - Binary buffer containing the model protobuf saved from a supported backend
@@ -111,6 +121,14 @@ AI.MODELSET resnet18 TF CPU INPUTS in1 OUTPUTS linear4 < foo.pb
 AI.MODELSET mnist_net ONNX CPU < mnist.onnx
 ```
 
+```sql
+AI.MODELSET mnist_net ONNX CPU BATCHSIZE 10 < mnist.onnx
+```
+
+```sql
+AI.MODELSET resnet18 TF CPU BATCHSIZE 10 MINBATCHSIZE 6 INPUTS in1 OUTPUTS linear4 < foo.pb
+```
+
 ## AI.MODELGET
 
 Get a model.

src/backends.c

@@ -74,7 +74,7 @@ int RAI_LoadBackend_TensorFlow(RedisModuleCtx *ctx, const char *path) {
   }
   init_backend(RedisModule_GetApi);
 
-  backend.model_create_with_nodes = (RAI_Model* (*)(RAI_Backend, const char*,
+  backend.model_create_with_nodes = (RAI_Model* (*)(RAI_Backend, const char*, RAI_ModelOpts,
                                      size_t, const char**, size_t, const char**,
                                      const char*, size_t, RAI_Error*))
                                      (unsigned long) dlsym(handle, "RAI_ModelCreateTF");
@@ -140,7 +140,7 @@ int RAI_LoadBackend_TFLite(RedisModuleCtx *ctx, const char *path) {
   }
   init_backend(RedisModule_GetApi);
 
-  backend.model_create = (RAI_Model* (*)(RAI_Backend, const char*,
+  backend.model_create = (RAI_Model* (*)(RAI_Backend, const char*, RAI_ModelOpts,
                           const char*, size_t, RAI_Error*))
                          (unsigned long) dlsym(handle, "RAI_ModelCreateTFLite");
   if (backend.model_create == NULL) {
@@ -205,7 +205,7 @@ int RAI_LoadBackend_Torch(RedisModuleCtx *ctx, const char *path) {
   }
   init_backend(RedisModule_GetApi);
 
-  backend.model_create = (RAI_Model* (*)(RAI_Backend, const char*,
+  backend.model_create = (RAI_Model* (*)(RAI_Backend, const char*, RAI_ModelOpts,
                           const char*, size_t, RAI_Error*))
                          (unsigned long) dlsym(handle, "RAI_ModelCreateTorch");
   if (backend.model_create == NULL) {
@@ -294,7 +294,7 @@ int RAI_LoadBackend_ONNXRuntime(RedisModuleCtx *ctx, const char *path) {
   }
   init_backend(RedisModule_GetApi);
 
-  backend.model_create = (RAI_Model* (*)(RAI_Backend, const char*,
+  backend.model_create = (RAI_Model* (*)(RAI_Backend, const char*, RAI_ModelOpts,
                           const char*, size_t, RAI_Error*))
                          (unsigned long) dlsym(handle, "RAI_ModelCreateORT");
   if (backend.model_create == NULL) {

src/backends.h

@@ -8,10 +8,10 @@
 #include "err.h"
 
 typedef struct RAI_LoadedBackend {
-  RAI_Model* (*model_create_with_nodes)(RAI_Backend, const char*,
+  RAI_Model* (*model_create_with_nodes)(RAI_Backend, const char*, RAI_ModelOpts,
                                         size_t, const char**, size_t, const char**,
                                         const char*, size_t, RAI_Error*);
-  RAI_Model* (*model_create)(RAI_Backend, const char*,
+  RAI_Model* (*model_create)(RAI_Backend, const char*, RAI_ModelOpts,
                              const char*, size_t, RAI_Error*);
   void (*model_free)(RAI_Model*, RAI_Error*);
   int (*model_run)(RAI_ModelRunCtx*, RAI_Error*);