[wasm] Add support for pthreads.

.gitignore

@@ -55,5 +55,6 @@ tensorflow-tfjs-*.tgz
 tfjs-backend-wasm/dist
 tfjs-backend-wasm/wasm-out/*.js
 tfjs-backend-wasm/wasm-out/*.wasm
+tfjs-backend-wasm/wasm-out/*.worker.ts
 yalc.lock
 yarn-error.log

tfjs-backend-wasm/README.md

@@ -73,24 +73,45 @@ bundlers such as Parcel and WebPack need to be able to serve the `.wasm` file in
 production. See [starter/parcel](./starter/parcel/) and
 [starter/webpack](./starter/webpack/) for how to setup your favorite bundler.
 
-If your server is serving the `.wasm` file on a different path or a different
-name, use `setWasmPath` before you initialize the backend:
+If you are serving the `.wasm` files from a different directory, call
+`setWasmPaths` with the location of that directory before you initialize the
+backend:
 
 ```ts
-import {setWasmPath} from '@tensorflow/tfjs-backend-wasm';
-setWasmPath(yourCustomPath); // or tf.wasm.setWasmPath when using <script> tags.
+import {setWasmPaths} from '@tensorflow/tfjs-backend-wasm';
+// setWasmPaths accepts a `prefix` argument which indicates the path to the
+// directory where your WASM binaries are located.
+setWasmPaths('www.yourdomain.com/'); // or tf.wasm.setWasmPaths when using <script> tags.
 tf.setBackend('wasm').then(() => {...});
 ```
 
-If you are using platform that does not support fetch directly, please set the
-optional `usePlatformFetch` to true:
+Note that if you call `setWasmPaths` with a `prefix`, it will be used to load
+each binary (SIMD-enabled, threading-enabled, etc.) However you can specify
+overrides for individual WASM binaries via the second `fileMap` argument of
+`setWasmPaths`. This is also helpful in case your binaries have been renamed.
+
+For example:
+
+```ts
+import {setWasmPaths} from '@tensorflow/tfjs-backend-wasm';
+setWasmPaths(null /* custom prefix */, {
+  'tfjs-backend-wasm.wasm': 'www.yourdomain.com/renamed.wasm',
+  'tfjs-backend-wasm-simd.wasm': 'www.yourdomain.com/renamed-simd.wasm',
+  'tfjs-backend-wasm-threaded-simd.wasm': 'www.yourdomain.com/renamed-threaded-simd.wasm'
+  });
+tf.setBackend('wasm').then(() => {...});
+```
+
+If you are using a platform that does not support fetch directly, please set the
+optional `usePlatformFetch` argument to `true`:
 
 ```ts
 import {setWasmPath} from '@tensorflow/tfjs-backend-wasm';
 const usePlatformFetch = true;
-setWasmPath(yourCustomPath, usePlatformFetch); // or tf.wasm.setWasmPath when using <script> tags.
+setWasmPaths(yourCustomPathPrefix, null /* file map */, usePlatformFetch);
 tf.setBackend('wasm').then(() => {...});
 ```
+
 ## Benchmarks
 
 The benchmarks below show inference times (ms) for two different edge-friendly
@@ -108,14 +129,14 @@ JS backend, and ~5.3-7.7X slower than the WebGL backend.
 
 <img src="./mobilenet-v2-bench.svg">
 
-| MobileNet inference (ms) | WASM  | WebGL | Plain JS | WASM + SIMD |
-|--------------------------|-------|-------|----------|-------------|
-| iPhone X                 | 147.1 | 20.3  | 941.3    | N/A         |
-| iPhone XS                | 140   | 18.1  | 426.4    | N/A         |
-| Pixel 3                  | 266.2 | 77.3  | 2345.2   | N/A         |
-| Desktop Linux            | 91.5  | 17.1  | 1049     | N/A         |
-| Desktop Windows          | 123.1 | 41.6  | 1117     | 37.2        |
-| Macbook Pro              | 98.4  | 19.6  | 893.5    | 30.2        |
+| MobileNet inference (ms) | WASM  | WebGL | Plain JS | WASM + SIMD | WASM + SIMD + threads
+|--------------------------|-------|-------|----------|-------------|----------------------
+| iPhone X                 | 147.1 | 20.3  | 941.3    | N/A         | N/A                 |
+| iPhone XS                | 140   | 18.1  | 426.4    | N/A         | N/A                 |
+| Pixel 4                  | 197.3 | 68.3  | 2228.2   | 142.4       | N/A                 |
+| Desktop Linux            | 91.5  | 17.1  | 1049     | 61.9        | 30.0                |
+| Desktop Windows          | 123.1 | 41.6  | 1117     | 37.2        | N/A                 |
+| Macbook Pro              | 98.4  | 19.6  | 893.5    | 30.2        | 10.3                |
 
 
 
@@ -128,14 +149,14 @@ the device).
 
 <img src="./face-detector-bench.svg">
 
-| Face Detector inference (ms) | WASM | WebGL | Plain JS | WASM + SIMD |
-|------------------------------|------|-------|----------|-------------|
-| iPhone X                     | 22.4 | 13.5  | 318      | N/A         |
-| iPhone XS                    | 21.4 | 10.5  | 176.9    | N/A         |
-| Pixel 3                      | 40.7 | 31.8  | 535.2    | N/A         |
-| Desktop Linux                | 12.6 | 12.7  | 249.5    | N/A         |
-| Desktop Windows              | 16.2 | 7.1   | 270.9    | 7.5         |
-| Macbook Pro 15 2019          | 13.6 | 22.7  | 209.1    | 7.9         |
+| Face Detector inference (ms) | WASM | WebGL | Plain JS | WASM + SIMD | WASM + SIMD + threads
+|------------------------------|------|-------|----------|-------------|----------------------
+| iPhone X                     | 22.4 | 13.5  | 318      | N/A         | N/A                 |
+| iPhone XS                    | 21.4 | 10.5  | 176.9    | N/A         | N/A                 |
+| Pixel 4                      | 32.2 | 30.6  | 478.8    | 24.0        | N/A                 |
+| Desktop Linux                | 12.6 | 12.7  | 249.5    | 8.0         | 6.2                 |
+| Desktop Windows              | 16.2 | 7.1   | 270.9    | 7.5         | N/A                 |
+| Macbook Pro 15 2019          | 13.6 | 22.7  | 209.1    | 7.9         | 4.0                 |
 
 # FAQ
 
@@ -168,12 +189,8 @@ inference as fast as possible.
 ### Do you work in node?
 Yes. If you run into issues, please let us know.
 
-### Do you support SIMD?
-Yes. We take advantage of SIMD wherever it is supported. If you intend to serve the WASM assets yourself, note that the SIMD-enabled WASM binary is separate from the default binary.
-
-### Do you support multi-threading?
-Multi-threading support is not a priority for us at this point since it is still
-a proposal. We will keep a close eye on it as the proposal progresses.
+### Do you support SIMD and multi-threading?
+Yes. We take advantage of SIMD and multi-threading wherever they are supported by testing the capabilities of your runtime and loading the appropriate WASM binary. If you intend to serve the WASM binaries from a custom location (via `setWasmPaths`), please note that the SIMD-enabled and threading-enabled binaries are separate from the regular binary.
 
 ### How do I give feedback?
 We'd love your feedback as we develop this backend! Please file an issue

tfjs-backend-wasm/karma.conf.js

@@ -20,9 +20,9 @@ const karmaTypescriptConfig = {
   compilerOptions: {allowJs: true, declaration: false},
   bundlerOptions: {
     sourceMap: true,
-    // Ignore the import of the `worker_threads` package used in a core test
-    // meant to run in node.
-    exclude: ['worker_threads'],
+    // Ignore the import of the `worker_threads`/`perf_hooks` packages meant to
+    // run in node.
+    exclude: ['worker_threads', 'perf_hooks'],
     // worker_node_test in tfjs-core contains a conditional require statement
     // that confuses the bundler of karma-typescript.
     ignore: ['./worker_node_test'],
@@ -61,6 +61,8 @@ module.exports = function(config) {
       {pattern: 'wasm-out/**/*.wasm', included: false},
       // Import the generated js library from emscripten.
       {pattern: 'wasm-out/**/*.js'},
+      // Import the generated worker file from emscripten.
+      {pattern: 'wasm-out/tfjs-backend-wasm-threaded-simd.worker.ts'},
       // Import the rest of the sources.
       {pattern: 'src/**/*.ts'},
     ],

tfjs-backend-wasm/package.json

@@ -16,6 +16,7 @@
     "build-deps": "cd ../tfjs-core && yarn && yarn build",
     "build-deps-ci": "cd ../tfjs-core && yarn && yarn build-ci",
     "build": "rimraf dist/ && tsc && ./scripts/build-wasm.sh",
+    "build-dev": "rimraf dist/ && tsc && ./scripts/build-wasm.sh --dev",
     "publish-local": "rimraf dist/ && yarn build && rollup -c && yalc push",
     "build-ci": "./scripts/build-ci.sh",
     "build-npm": "./scripts/build-npm.sh",
@@ -25,6 +26,7 @@
     "cpplint": "./scripts/cpplint.js",
     "lint": "tslint -p . -t verbose && yarn cpplint",
     "test": "yarn && yarn build-deps && yarn build && karma start",
+    "test-dev": "yarn && yarn build-deps && yarn build-dev && karma start",
     "test-ci": "./scripts/test-ci.sh",
     "test-node": "ts-node --skip-ignore -P tsconfig.test.json src/test_node.ts",
     "test-bundle-size": "./scripts/test-bundle-size.js",

tfjs-backend-wasm/scripts/build-benchmark.sh

@@ -4,3 +4,4 @@ yarn rollup -c
 cp dist/tf-backend-wasm.js ../e2e/benchmarks/
 cp wasm-out/tfjs-backend-wasm.wasm ../e2e/benchmarks/
 cp wasm-out/tfjs-backend-wasm-simd.wasm ../e2e/benchmarks/
+cp wasm-out/tfjs-backend-wasm-threaded-simd.wasm ../e2e/benchmarks/

tfjs-backend-wasm/scripts/build-wasm.sh

@@ -24,12 +24,22 @@ cp -f bazel-bin/src/cc/tfjs-backend-wasm.js \
       bazel-bin/src/cc/tfjs-backend-wasm.wasm \
       wasm-out/
 
-# SIMD build.
-yarn bazel build -c opt //src/cc:tfjs-backend-wasm-simd.js --config=wasm --copt="-msimd128"
-cp -f bazel-bin/src/cc/tfjs-backend-wasm-simd.js \
-      bazel-bin/src/cc/tfjs-backend-wasm-simd.wasm \
-      wasm-out/
+if [[ "$1" != "--dev" ]]; then
+  # SIMD build.
+  yarn bazel build -c opt //src/cc:tfjs-backend-wasm-simd.wasm --config=wasm --copt="-msimd128"
+  cp -f bazel-bin/src/cc/tfjs-backend-wasm-simd.wasm \
+        wasm-out/
+
+  # Threaded + SIMD build.
+  yarn bazel build -c opt //src/cc:tfjs-backend-wasm-threaded-simd.js --config=wasm --copt="-pthread" --copt="-msimd128"
+  cp -f bazel-bin/src/cc/tfjs-backend-wasm-threaded-simd.js \
+        bazel-bin/src/cc/tfjs-backend-wasm-threaded-simd.worker.js \
+        bazel-bin/src/cc/tfjs-backend-wasm-threaded-simd.wasm \
+        wasm-out/
+
+  node ./scripts/create-worker-module.js
+fi
 
 mkdir -p dist
-# Only copying binary into dist because the js module gets bundled.
+# Only copying binaries into dist because the js modules get bundled.
 cp wasm-out/*.wasm dist/

tfjs-backend-wasm/scripts/create-worker-module.js

@@ -0,0 +1,35 @@
+/**
+ * @license
+ * Copyright 2020 Google LLC. All Rights Reserved.
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ * =============================================================================
+ */
+
+/**
+ * This file creates a TypeScript module that exports the contents of the
+ * Emscripten-generated WASM worker script so that it can be inlined by the
+ * tf-backend-wasm bundle.
+ */
+
+const fs = require('fs');
+
+const BASE_PATH = './wasm-out/';
+const WORKER_PATH = `${BASE_PATH}tfjs-backend-wasm-threaded-simd.worker.js`;
+
+// Write out a worker TypeScript module.
+const workerContents = fs.readFileSync(WORKER_PATH, "utf8");
+fs.writeFileSync(`${BASE_PATH}tfjs-backend-wasm-threaded-simd.worker.ts`,
+  `export const wasmWorkerContents = '${workerContents.trim()}';`);
+
+// Delete the original worker file.
+fs.unlinkSync(WORKER_PATH)