[core] Add hooks for setting experimental thread priorities for mbgl threads

src/core-files.json

@@ -62,6 +62,7 @@
         "src/mbgl/map/transform_state.cpp",
         "src/mbgl/math/log2.cpp",
         "src/mbgl/platform/gl_functions.cpp",
+        "src/mbgl/platform/settings.cpp",
         "src/mbgl/programs/background_program.cpp",
         "src/mbgl/programs/circle_program.cpp",
         "src/mbgl/programs/clipping_mask_program.cpp",
@@ -316,6 +317,7 @@
         "src/mbgl/util/rapidjson.cpp",
         "src/mbgl/util/stopwatch.cpp",
         "src/mbgl/util/string.cpp",
+        "src/mbgl/util/thread.cpp",
         "src/mbgl/util/thread_pool.cpp",
         "src/mbgl/util/tile_cover.cpp",
         "src/mbgl/util/tile_cover_impl.cpp",
@@ -369,6 +371,7 @@
         "mbgl/math/minmax.hpp": "include/mbgl/math/minmax.hpp",
         "mbgl/math/wrap.hpp": "include/mbgl/math/wrap.hpp",
         "mbgl/platform/gl_functions.hpp": "include/mbgl/platform/gl_functions.hpp",
+        "mbgl/platform/settings.hpp": "include/mbgl/platform/settings.hpp",
         "mbgl/platform/thread.hpp": "include/mbgl/platform/thread.hpp",
         "mbgl/renderer/query.hpp": "include/mbgl/renderer/query.hpp",
         "mbgl/renderer/renderer.hpp": "include/mbgl/renderer/renderer.hpp",

src/mbgl/util/thread.cpp

@@ -0,0 +1,19 @@
+#include <functional>
+#include <mbgl/platform/settings.hpp>
+#include <mbgl/util/platform.hpp>
+
+namespace mbgl {
+namespace util {
+std::function<void()> makeThreadPrioritySetter(std::string threadType_) {
+    return [threadType = std::move(threadType_)] {
+        auto& settings = platform::Settings::getInstance();
+        auto value = settings.get(threadType);
+        if (auto* priority = value.getDouble()) {
+            platform::setCurrentThreadPriority(*priority);
+        } else {
+            platform::makeThreadLowPriority();
+        }
+    };
+}
+} // namespace util
+} // namespace mbgl

src/mbgl/util/thread_pool.cpp

@@ -1,8 +1,9 @@
 #include <mbgl/util/thread_pool.hpp>
 
+#include <mbgl/platform/settings.hpp>
+#include <mbgl/platform/thread.hpp>
 #include <mbgl/util/platform.hpp>
 #include <mbgl/util/string.hpp>
-#include <mbgl/platform/thread.hpp>
 
 namespace mbgl {
 
@@ -17,7 +18,13 @@ void ThreadedSchedulerBase::terminate() {
 }
 
 std::thread ThreadedSchedulerBase::makeSchedulerThread(size_t index) {
-    return std::thread([this, index]() {
+    return std::thread([this, index] {
+        auto& settings = platform::Settings::getInstance();
+        auto value = settings.get(platform::EXPERIMENTAL_THREAD_PRIORITY_WORKER);
+        if (auto* priority = value.getDouble()) {
+            platform::setCurrentThreadPriority(*priority);
+        }
+
         platform::setCurrentThreadName(std::string{"Worker "} + util::toString(index + 1));
         platform::attachThread();