feat(//py): Allowing people using the PyTorch backend to use TRTorch/TRT

INT8 calibrators

Signed-off-by: Naren Dasan <naren@narendasan.com>
Signed-off-by: Naren Dasan <narens@nvidia.com>

.gitignore

@@ -5,6 +5,7 @@ bazel-genfiles
 bazel-out
 bazel-testlogs
 bazel-TRTorch
+bazel-trtorch-testing
 third_party/pytorch
 *.jit
 *.jit.pt
@@ -37,4 +38,6 @@ bdist
 py/trtorch/_version.py
 py/wheelhouse
 py/.eggs
-notebooks/.ipynb_checkpoints/
+notebooks/.ipynb_checkpoints/
+*.cache
+tests/py/data

py/trtorch/_compile_spec.py

@@ -257,5 +257,6 @@ def TensorRTCompileSpec(compile_spec: Dict[str, Any]) -> torch.classes.tensorrt.
     backend_spec.set_num_avg_timing_iters(parsed_spec.num_avg_timing_iters)
     backend_spec.set_workspace_size(parsed_spec.workspace_size)
     backend_spec.set_max_batch_size(parsed_spec.max_batch_size)
+    backend_spec._set_ptq_calibrator(parsed_spec._get_calibrator_handle())
 
     return backend_spec

py/trtorch/csrc/register_tensorrt_classes.cpp

@@ -29,6 +29,7 @@ void RegisterTRTCompileSpec() {
           .def(torch::init<>())
           .def("append_input_range", &trtorch::pyapi::CompileSpec::appendInputRange)
           .def("set_device", &trtorch::pyapi::CompileSpec::setDeviceIntrusive)
+          .def("_set_ptq_calibrator", &trtorch::pyapi::CompileSpec::setPTQCalibratorViaHandle)
           .def("__str__", &trtorch::pyapi::CompileSpec::stringify);
 
   ADD_FIELD_GET_SET_REGISTRATION(TRTCompileSpecTSRegistration, trtorch::pyapi::CompileSpec, op_precision);

py/trtorch/csrc/tensorrt_classes.h

@@ -94,10 +94,18 @@ struct CompileSpec : torch::CustomClassHolder {
     input_ranges.push_back(*ir);
   }
 
+  int64_t getPTQCalibratorHandle() {
+    return (int64_t)ptq_calibrator;
+  }
+
   void setDeviceIntrusive(const c10::intrusive_ptr<Device>& d) {
     device = *d;
   }
 
+  void setPTQCalibratorViaHandle(int64_t handle) {
+    ptq_calibrator = (nvinfer1::IInt8Calibrator*)handle;
+  }
+
   ADD_ENUM_GET_SET(op_precision, DataType, static_cast<int64_t>(DataType::kChar));
   ADD_FIELD_GET_SET(disable_tf32, bool);
   ADD_FIELD_GET_SET(refit, bool);

py/trtorch/csrc/trtorch_py.cpp

@@ -234,6 +234,7 @@ PYBIND11_MODULE(_C, m) {
 
   py::class_<CompileSpec>(m, "CompileSpec")
       .def(py::init<>())
+      .def("_get_calibrator_handle", &CompileSpec::getPTQCalibratorHandle, "[Internal] gets a handle from a calibrator")
       .def_readwrite("input_ranges", &CompileSpec::input_ranges)
       .def_readwrite("op_precision", &CompileSpec::op_precision)
       .def_readwrite("ptq_calibrator", &CompileSpec::ptq_calibrator)

tests/py/test_ptq_to_backend.py

@@ -0,0 +1,97 @@
+import unittest
+import trtorch
+from trtorch.logging import *
+import torch
+import torch.nn as nn
+from torch.nn import functional as F
+import torchvision
+import torchvision.transforms as transforms
+from model_test_case import ModelTestCase
+
+
+class TestAccuracy(ModelTestCase):
+
+    def setUp(self):
+        self.input = torch.randn((1, 3, 32, 32)).to("cuda")
+        self.testing_dataset = torchvision.datasets.CIFAR10(root='./data',
+                                                            train=False,
+                                                            download=True,
+                                                            transform=transforms.Compose([
+                                                                transforms.ToTensor(),
+                                                                transforms.Normalize((0.4914, 0.4822, 0.4465),
+                                                                                     (0.2023, 0.1994, 0.2010))
+                                                            ]))
+
+        self.testing_dataloader = torch.utils.data.DataLoader(self.testing_dataset,
+                                                              batch_size=1,
+                                                              shuffle=False,
+                                                              num_workers=1)
+        self.calibrator = trtorch.ptq.DataLoaderCalibrator(self.testing_dataloader,
+                                                           cache_file='./calibration.cache',
+                                                           use_cache=False,
+                                                           algo_type=trtorch.ptq.CalibrationAlgo.ENTROPY_CALIBRATION_2,
+                                                           device=torch.device('cuda:0'))
+
+        self.spec = {
+            "forward":
+                trtorch.TensorRTCompileSpec({
+                    "input_shapes": [[1, 3, 32, 32]],
+                    "op_precision": torch.int8,
+                    "calibrator": self.calibrator,
+                    "device": {
+                        "device_type": trtorch.DeviceType.GPU,
+                        "gpu_id": 0,
+                        "dla_core": 0,
+                        "allow_gpu_fallback": False,
+                    }
+                })
+        }
+
+    def compute_accuracy(self, testing_dataloader, model):
+        total = 0
+        correct = 0
+        loss = 0.0
+        class_probs = []
+        class_preds = []
+
+        with torch.no_grad():
+            idx = 0
+            for data, labels in testing_dataloader:
+                data, labels = data.cuda(), labels.cuda(non_blocking=True)
+                out = model(data)
+                preds = torch.max(out, 1)[1]
+                class_probs.append([F.softmax(i, dim=0) for i in out])
+                class_preds.append(preds)
+                total += labels.size(0)
+                correct += (preds == labels).sum().item()
+                idx += 1
+
+        test_probs = torch.cat([torch.stack(batch) for batch in class_probs])
+        test_preds = torch.cat(class_preds)
+        return correct / total
+
+    def test_compile_script(self):
+
+        fp32_test_acc = self.compute_accuracy(self.testing_dataloader, self.model)
+        log(Level.Info, "[Pyt FP32] Test Acc: {:.2f}%".format(100 * fp32_test_acc))
+
+        trt_mod = torch._C._jit_to_backend("tensorrt", self.model, self.spec)
+        int8_test_acc = self.compute_accuracy(self.testing_dataloader, trt_mod)
+        log(Level.Info, "[TRT INT8 Backend] Test Acc: {:.2f}%".format(100 * int8_test_acc))
+        acc_diff = fp32_test_acc - int8_test_acc
+        self.assertTrue(abs(acc_diff) < 3)
+
+
+def test_suite():
+    suite = unittest.TestSuite()
+    suite.addTest(TestAccuracy.parametrize(TestAccuracy, model=torch.jit.load('./trained_vgg16.jit.pt')))
+
+    return suite
+
+
+suite = test_suite()
+
+runner = unittest.TextTestRunner()
+result = runner.run(suite)
+
+exit(int(not result.wasSuccessful()))