use separate workers for tile parsing to avoid blocking the threadpool for other libuv actions

4 files changed, 29 insertions, 14 deletions

diff --git a/include/mbgl/map/map.hpp b/include/mbgl/map/map.hpp
index 786c7196ae..c389d898b1 100644
--- a/include/mbgl/map/map.hpp
+++ b/include/mbgl/map/map.hpp
@@ -126,6 +126,7 @@ public:
     util::ptr<Sprite> getSprite();
     inline util::ptr<Texturepool> getTexturepool() { return texturepool; }
     inline util::ptr<uv::loop> getLoop() { return loop; }
+    uv::worker &getWorker();
     inline timestamp getAnimationTime() const { return animationTime; }
     inline timestamp getTime() const { return animationTime; }
     void updateTiles();
@@ -159,6 +160,7 @@ private:
 private:
     bool async = false;
     util::ptr<uv::loop> loop;
+    std::unique_ptr<uv::worker> workers;
     std::unique_ptr<uv::thread> thread;
     std::unique_ptr<uv_async_t> async_terminate;
     std::unique_ptr<uv_async_t> async_render;
diff --git a/include/mbgl/util/uv-worker.h b/include/mbgl/util/uv-worker.h
index b9eb10fb70..a66feb4d00 100644
--- a/include/mbgl/util/uv-worker.h
+++ b/include/mbgl/util/uv-worker.h
@@ -14,17 +14,16 @@ typedef struct uv_messenger_s uv_messenger_t;
 typedef struct uv_worker_s uv_worker_t;
 
 struct uv_worker_s {
-    uv_thread_t thread;
     uv_messenger_t *msgr;
     uv_chan_t chan;
     const char *name;
+    void *threads[2];
 };
 
 typedef void (*uv_worker_cb)(void *data);
 typedef void (*uv_worker_after_cb)(void *data);
 
-int uv_worker_init(uv_worker_t *worker, uv_loop_t *loop);
-int uv_worker_init_named(uv_worker_t *worker, uv_loop_t *loop, const char *name);
+int uv_worker_init(uv_worker_t *worker, uv_loop_t *loop, int count, const char *name);
 void uv_worker_send(uv_worker_t *worker, void *data, uv_worker_cb work_cb,
                     uv_worker_after_cb after_work_cb);
 void uv_worker_close(uv_worker_t *worker);
diff --git a/include/mbgl/util/uv.hpp b/include/mbgl/util/uv.hpp
index 4ceb8b873f..80fff9c96f 100644
--- a/include/mbgl/util/uv.hpp
+++ b/include/mbgl/util/uv.hpp
@@ -14,6 +14,7 @@ std::string cwd();
 class thread;
 class rwlock;
 class loop;
+class worker;
 
 }
 
diff --git a/include/mbgl/util/uv_detail.hpp b/include/mbgl/util/uv_detail.hpp
index 272ca41495..b0b4fe583f 100644
--- a/include/mbgl/util/uv_detail.hpp
+++ b/include/mbgl/util/uv_detail.hpp
@@ -2,6 +2,7 @@
 #define MBGL_UTIL_UV_DETAIL
 
 #include <mbgl/util/ptr.hpp>
+#include <mbgl/util/uv-worker.h>
 
 #include <uv.h>
 
@@ -108,6 +109,22 @@ private:
     uv_once_t o = UV_ONCE_INIT;
 };
 
+class worker {
+public:
+    inline worker(uv_loop_t *loop, unsigned int count, const char *name = nullptr) {
+        uv_worker_init(&w, loop, count, name);
+    }
+    inline ~worker() {
+        uv_worker_close(&w);
+    }
+    inline void add(void *data, uv_worker_cb work_cb, uv_worker_after_cb after_work_cb) {
+        uv_worker_send(&w, data, work_cb, after_work_cb);
+    }
+
+private:
+    uv_worker_t w;
+};
+
 template <typename T>
 class work {
 public:
@@ -115,30 +132,26 @@ public:
     typedef void (*after_work_callback)(T &object);
 
     template<typename... Args>
-    work(const mbgl::util::ptr<loop> &loop, work_callback work_cb, after_work_callback after_work_cb, Args&&... args)
-        : loop(loop),
-          data(std::forward<Args>(args)...),
+    work(worker &worker, work_callback work_cb, after_work_callback after_work_cb, Args&&... args)
+        : data(std::forward<Args>(args)...),
           work_cb(work_cb),
           after_work_cb(after_work_cb) {
-        req.data = this;
-        uv_queue_work(**loop, &req, do_work, after_work);
+        worker.add(this, do_work, after_work);
     }
 
 private:
-    static void do_work(uv_work_t *req) {
-        work<T> *w = static_cast<work<T> *>(req->data);
+    static void do_work(void *data) {
+        work<T> *w = reinterpret_cast<work<T> *>(data);
         w->work_cb(w->data);
     }
 
-    static void after_work(uv_work_t *req, int) {
-        work<T> *w = static_cast<work<T> *>(req->data);
+    static void after_work(void *data) {
+        work<T> *w = reinterpret_cast<work<T> *>(data);
         w->after_work_cb(w->data);
         delete w;
     }
 
 private:
-    mbgl::util::ptr<uv::loop> loop;
-    uv_work_t req;
     T data;
     work_callback work_cb;
     after_work_callback after_work_cb;