Update docs for quantization usage

docs/user_guide/quantization_usage.rst

@@ -13,14 +13,19 @@ Refer to `Tensorflow quantization-aware training <https://github.com/tensorflow/
 After pre-training model using float point, estimate output range of each activation layer using sample inputs.
 
 
+.. note::
+
+  `quantize_weights` and `quantize_nodes` should not be specified when using `TransformGraph` tool if using MACE quantization.
+
+
 Quantization-aware training
 ----------------------------
 It is recommended that developers fine tune the fixed-point model, as experiments show that by this way accuracy could be improved, especially for lightweight
 models, e.g., MobileNet. The only thing you need to make it run using MACE is to add the following config to model yaml file:
 
-	1. `input_ranges`: the ranges of model's inputs, e.g., -1.0,1.0.
+  1. `input_ranges`: the ranges of model's inputs, e.g., -1.0,1.0.
 
-	2. `quantize`: set `quantize` to be 1.
+  2. `quantize`: set `quantize` to be 1.
 
 
 Post training quantization
@@ -29,46 +34,81 @@ MACE supports post-training quantization if you want to take a chance to quantiz
 This method requires developer to calculate tensor range of each activation layer statistically using sample inputs.
 MACE provides tools to do statistics with following steps:
 
-	1. Convert original model to run on CPU host without obfuscation (by setting `target_abis` to `host`, `runtime` to `cpu`,
-	and `obfuscate` to `0`, appending `:0` to `output_tensors` if missing in yaml config). 
+  1. Convert original model to run on CPU host without obfuscation (by setting `target_abis` to `host`, `runtime` to `cpu`,
+  and `obfuscate` to `0`, appending `:0` to `output_tensors` if missing in yaml config). 
 
-	2. Log tensor range of each activation layer by inferring several samples on CPU host. Sample inputs should be
-	representative to calculate the ranges of each layer properly.
+  2. Log tensor range of each activation layer by inferring several samples on CPU host. Sample inputs should be
+  representative to calculate the ranges of each layer properly.
 
-	.. code-block:: sh
+  .. code-block:: sh
 
-		# Convert images to input tensors for MACE, see image_to_tensor.py for more arguments.
-		python tools/image/image_to_tensor.py --input /path/to/directory/of/input/images
-			--output_dir /path/to/directory/of/input/tensors --image_shape=299,299,3
+    # Convert images to input tensors for MACE, see image_to_tensor.py for more arguments.
+    python tools/image/image_to_tensor.py --input /path/to/directory/of/input/images
+      --output_dir /path/to/directory/of/input/tensors --image_shape=299,299,3
 
-		# Rename input tensors to start with input tensor name(to differentiate multiple
-		# inputs of a model), input tensor name is what you specified as "input_tensors"
-		# in yaml config. For example, "input" is the input tensor name of InceptionV3 as below.
-		rename 's/^/input/' *
+    # Rename input tensors to start with input tensor name(to differentiate multiple
+    # inputs of a model), input tensor name is what you specified as "input_tensors"
+    # in yaml config. For example, "input" is the input tensor name of InceptionV3 as below.
+    rename 's/^/input/' *
 
-		# Run with input tensors
-		# For CMake users:
-		python tools/python/run_model.py --config ../mace-models/inception-v3/inception-v3.yml
-			--quantize_stat --input_dir /path/to/directory/of/input/tensors > range_log
+    # Run with input tensors
+    # For CMake users:
+    python tools/python/run_model.py --config ../mace-models/inception-v3/inception-v3.yml
+      --quantize_stat --input_dir /path/to/directory/of/input/tensors > range_log
 
-		# For Bazel users:
-		python tools/converter.py run --config ../mace-models/inception-v3/inception-v3.yml
-			--quantize_stat --input_dir /path/to/directory/of/input/tensors > range_log
+    # For Bazel users:
+    python tools/converter.py run --config ../mace-models/inception-v3/inception-v3.yml
+      --quantize_stat --input_dir /path/to/directory/of/input/tensors > range_log
 
 
-	3. Calculate overall range of each activation layer. You may specify `--percentile` or `--enhance` and `--enhance_ratio`
-	to try different ranges and see which is better. Experimentation shows that the default `percentile` and `enhance_ratio`
-	works fine for several common models.
+  3. Calculate overall range of each activation layer. You may specify `--percentile` or `--enhance` and `--enhance_ratio`
+  to try different ranges and see which is better. Experimentation shows that the default `percentile` and `enhance_ratio`
+  works fine for several common models.
 
-	.. code-block:: sh
+  .. code-block:: sh
 
-		python tools/python/quantize/quantize_stat.py --log_file range_log > overall_range
+    python tools/python/quantize/quantize_stat.py --log_file range_log > overall_range
 
 
-	4. Convert quantized model (by setting `target_abis` to the final target abis, e.g., `armeabi-v7a`,
-	`quantize` to `1` and `quantize_range_file` to the overall_range file path in yaml config).
+  4. Convert quantized model (by setting `target_abis` to the final target abis, e.g., `armeabi-v7a`,
+  `quantize` to `1` and `quantize_range_file` to the overall_range file path in yaml config).
 
 
-.. note::
+Supported devices
+-----------------
+MACE supports running quantized models on ARM CPU and other acceleration devices, e.g., Qualcomm Hexagon DSP, MediaTek APU.
+ARM CPU is ubiquitous, which can speed up most of edge devices. However, AI specialized devices may run much faster
+than ARM CPU, and in the meantime consume much lower power. Headers and libraries of these devices can be found in `third_party`
+directory.
+
+* **To run models on Hexagon DSP, users should**
+
+  1. Make sure SOCs of the phone is manufactured by Qualcomm and has HVX supported.
+
+  2. Make sure the phone disables secure boot (once enabled, cannot be reversed, so you probably can only get that type
+     phones from manufacturers). This can be checked by executing the following command.
+
+   .. code-block:: sh
+
+       adb shell getprop ro.boot.secureboot
+
+   The return value should be 0.
+
+  3. Root the phone.
+
+  4. Sign the phone by using testsig provided by Qualcomm. (Download Qualcomm Hexagon SDK first, plugin the phone to PC,
+     run scripts/testsig.py)
+
+  5. Push `third_party/nnlib/v6x/libhexagon_nn_skel.so` to `/system/vendor/lib/rfsa/adsp/`. You can check
+     `docs/feature_matrix.html` in Hexagon SDK to make sure which version to use.
+
+Then, there you go, you can run Mace on Hexagon DSP. This indeed seems like a whole lot of work to do. Well, the good news
+is that starting in the SM8150 family(some devices with old firmware may still not work), signature-free dynamic
+module offload is enabled on cDSP. So, steps 2-4 can be skipped. This can be achieved by calling `SetHexagonToUnsignedPD()`
+before creating MACE engine.
+
+* **To run models on MediaTek APU, users should**
+
+  1. Make sure SOCs of the phone is manufactured by MediaTek and has APU supported.
 
-	`quantize_weights` and `quantize_nodes` should not be specified when using `TransformGraph` tool if using MACE quantization.
+  2. Push `third_party/apu/mtxxxx/libapu-platform.so` to `/vendor/lib64/`.