skpbench: add option for gpu timing

tools/gpu/GpuTimer.h

+/*
+ * Copyright 2016 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#ifndef GpuTimer_DEFINED
+#define GpuTimer_DEFINED
+
+#include "SkTypes.h"
+#include "SkExchange.h"
+#include <chrono>
+
+namespace sk_gpu_test {
+
+using PlatformGpuTimerQuery = intptr_t;
+constexpr static PlatformGpuTimerQuery kInvalidGpuTimerQuery = 0;
+
+/**
+ * Platform-independent interface for timing operations on the GPU.
+ */
+class GpuTimer {
+public:
+    GpuTimer(bool disjointSupport)
+        : fDisjointSupport(disjointSupport)
+        , fActiveTimer(kInvalidGpuTimerQuery) {
+    }
+    virtual ~GpuTimer() { SkASSERT(!fActiveTimer); }
+
+    /**
+     * Returns whether this timer can detect disjoint GPU operations while timing. If false, a query
+     * has less confidence when it completes with QueryStatus::kAccurate.
+     */
+    bool disjointSupport() const { return fDisjointSupport; }
+
+    /**
+     * Inserts a "start timing" command in the GPU command stream.
+     */
+    void queueStart() {
+        SkASSERT(!fActiveTimer);
+        fActiveTimer = this->onQueueTimerStart();
+    }
+
+    /**
+     * Inserts a "stop timing" command in the GPU command stream.
+     *
+     * @return a query object that can retrieve the time elapsed once the timer has completed.
+     */
+    PlatformGpuTimerQuery SK_WARN_UNUSED_RESULT queueStop() {
+        SkASSERT(fActiveTimer);
+        this->onQueueTimerStop(fActiveTimer);
+        return skstd::exchange(fActiveTimer, kInvalidGpuTimerQuery);
+    }
+
+    enum class QueryStatus {
+        kInvalid,  //<! the timer query is invalid.
+        kPending,  //<! the timer is still running on the GPU.
+        kDisjoint, //<! the query is complete, but dubious due to disjoint GPU operations.
+        kAccurate  //<! the query is complete and reliable.
+    };
+
+    virtual QueryStatus checkQueryStatus(PlatformGpuTimerQuery) = 0;
+    virtual std::chrono::nanoseconds getTimeElapsed(PlatformGpuTimerQuery) = 0;
+    virtual void deleteQuery(PlatformGpuTimerQuery) = 0;
+
+private:
+    virtual PlatformGpuTimerQuery onQueueTimerStart() const = 0;
+    virtual void onQueueTimerStop(PlatformGpuTimerQuery) const = 0;
+
+    bool const              fDisjointSupport;
+    PlatformGpuTimerQuery   fActiveTimer;
+};
+
+}

[bsalomon, 2016/10/04 18:00:01]

I think most of the other files in here would have a // namespace sk_gpu_test
here.

[csmartdalton, 2016/10/04 19:06:35]

Done.

+
+#endif