Implement SkGLContext swapBuffers with fence syncs

bench/nanobench.cpp

 /*
  * Copyright 2014 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include <ctype.h>
 
 #include "nanobench.h"
@@ skipping 61 matching lines @@
     return help;
 }
 
 DEFINE_int32(loops, kDefaultLoops, loops_help_txt().c_str());
 
 DEFINE_int32(samples, 10, "Number of samples to measure for each bench.");
 DEFINE_int32(overheadLoops, 100000, "Loops to estimate timer overhead.");
 DEFINE_double(overheadGoal, 0.0001,
               "Loop until timer overhead is at most this fraction of our measurments.");
 DEFINE_double(gpuMs, 5, "Target bench time in millseconds for GPU.");
-DEFINE_int32(gpuFrameLag, 5, "Overestimate of maximum number of frames GPU allows to lag.");
+DEFINE_int32(gpuFrameLag, 5, "If unknown, estimated maximum number of frames GPU allows to lag.");
 DEFINE_bool(gpuCompressAlphaMasks, false, "Compress masks generated from falling back to "
                                           "software path rendering.");
 
 DEFINE_string(outResultsFile, "", "If given, write results here as JSON.");
 DEFINE_int32(maxCalibrationAttempts, 3,
              "Try up to this many times to guess loops for a bench, or skip the bench.");
 DEFINE_int32(maxLoops, 1000000, "Never run a bench more times than this.");
 DEFINE_string(clip, "0,0,1000,1000", "Clip for SKPs.");
 DEFINE_string(scales, "1.0", "Space-separated scales for SKPs.");
 DEFINE_string(zoom, "1.0,1", "Comma-separated scale,step zoom factors for SKPs.");
@@ skipping 44 matching lines @@
     void endTiming() override {
         if (this->gl) {
             SK_GL(*this->gl, Flush());
             this->gl->swapBuffers();
         }
     }
     void fence() override {
         SK_GL(*this->gl, Finish());
     }
 
-    bool needsFrameTiming() const override { return true; }
+    bool needsFrameTiming(int* maxFrameLag) const override {
+        if (!this->gl->getMaxGpuFrameLag(maxFrameLag)) {
+            // Frame lag is unknown.
+            *maxFrameLag = FLAGS_gpuFrameLag;
+        }
+        return true;
+    }
     bool init(SkImageInfo info, Benchmark* bench) override {
         uint32_t flags = this->config.useDFText ? SkSurfaceProps::kUseDistanceFieldFonts_Flag : 0;
         SkSurfaceProps props(flags, SkSurfaceProps::kLegacyFontHost_InitType);
         this->surface.reset(SkSurface::NewRenderTarget(gGrFactory->get(this->config.ctxType),
                                                          SkSurface::kNo_Budgeted, info,
                                                          this->config.samples, &props));
         this->gl = gGrFactory->getGLContext(this->config.ctxType);
         if (!this->surface.get()) {
             return false;
         }
+        if (!this->gl->fenceSyncSupport()) {
+            SkDebugf("WARNING: GL context for config \"%s\" does not support fence sync. "
+                     "Timings might not be accurate.\n", this->config.name);
+        }
         return true;
     }
     void fillOptions(ResultsWriter* log) override {
         const GrGLubyte* version;
         SK_GL_RET(*this->gl, version, GetString(GR_GL_VERSION));
         log->configOption("GL_VERSION", (const char*)(version));
 
         SK_GL_RET(*this->gl, version, GetString(GR_GL_RENDERER));
         log->configOption("GL_RENDERER", (const char*) version);
 
@@ skipping 132 matching lines @@
     }
 
     for (int i = 0; i < FLAGS_samples; i++) {
         samples[i] = time(loops, bench, target) / loops;
     }
     return loops;
 }
 
 static int gpu_bench(Target* target,
                      Benchmark* bench,
-                     double* samples) {
+                     double* samples,
+                     int maxGpuFrameLag) {
     // First, figure out how many loops it'll take to get a frame up to FLAGS_gpuMs.
     int loops = FLAGS_loops;
     if (kAutoTuneLoops == loops) {
         loops = 1;
         double elapsed = 0;
         do {
             if (1<<30 == loops) {
                 // We're about to wrap.  Something's wrong with the bench.
                 loops = 0;
                 break;
             }
             loops *= 2;
             // If the GPU lets frames lag at all, we need to make sure we're timing
-            // _this_ round, not still timing last round.  We force this by looping
-            // more times than any reasonable GPU will allow frames to lag.
-            for (int i = 0; i < FLAGS_gpuFrameLag; i++) {
+            // _this_ round, not still timing last round.
+            for (int i = 0; i < maxGpuFrameLag; i++) {
                 elapsed = time(loops, bench, target);
             }
         } while (elapsed < FLAGS_gpuMs);
 
         // We've overshot at least a little.  Scale back linearly.
         loops = (int)ceil(loops * FLAGS_gpuMs / elapsed);
         loops = clamp_loops(loops);
 
         // Make sure we're not still timing our calibration.
         target->fence();
     } else {
         loops = detect_forever_loops(loops);
     }
 
     // Pretty much the same deal as the calibration: do some warmup to make
     // sure we're timing steady-state pipelined frames.
-    for (int i = 0; i < FLAGS_gpuFrameLag; i++) {
+    for (int i = 0; i < maxGpuFrameLag - 1; i++) {
         time(loops, bench, target);
     }
 
     // Now, actually do the timing!
     for (int i = 0; i < FLAGS_samples; i++) {
         samples[i] = time(loops, bench, target) / loops;
     }
 
     return loops;
 }
@@ skipping 68 matching lines @@
         GPU_CONFIG(msaa4, kNative_GLContextType, 4, false)
         GPU_CONFIG(msaa16, kNative_GLContextType, 16, false)
         GPU_CONFIG(nvprmsaa4, kNVPR_GLContextType, 4, false)
         GPU_CONFIG(nvprmsaa16, kNVPR_GLContextType, 16, false)
         GPU_CONFIG(gpudft, kNative_GLContextType, 0, true)
         GPU_CONFIG(debug, kDebug_GLContextType, 0, false)
         GPU_CONFIG(nullgpu, kNull_GLContextType, 0, false)
 #ifdef SK_ANGLE
         GPU_CONFIG(angle, kANGLE_GLContextType, 0, false)
 #endif
+#if SK_MESA
+        GPU_CONFIG(mesa, kMESA_GLContextType, 0, false)
+#endif
     }
 #endif
 
 #ifdef SK_BUILD_FOR_ANDROID_FRAMEWORK
     if (is_cpu_config_allowed("hwui")) {
         Config config = { "hwui", Benchmark::kHWUI_Backend, kRGBA_8888_SkColorType,
                           kPremul_SkAlphaType, 0, kBogusGLContextType, false };
         configs->push(config);
     }
 #endif
@@ skipping 559 matching lines @@
             bench->preDraw();
         }
         for (int j = 0; j < targets.count(); j++) {
             // During HWUI output this canvas may be NULL.
             SkCanvas* canvas = targets[j]->getCanvas();
             const char* config = targets[j]->config.name;
 
             targets[j]->setup();
             bench->perCanvasPreDraw(canvas);
 
+            int frameLag;
             const int loops =
-                targets[j]->needsFrameTiming()
-                ? gpu_bench(targets[j], bench.get(), samples.get())
+                targets[j]->needsFrameTiming(&frameLag)
+                ? gpu_bench(targets[j], bench.get(), samples.get(), frameLag)
                 : cpu_bench(overhead, targets[j], bench.get(), samples.get());
 
             bench->perCanvasPostDraw(canvas);
 
             if (Benchmark::kNonRendering_Backend != targets[j]->config.backend &&
                 !FLAGS_writePath.isEmpty() && FLAGS_writePath[0]) {
                 SkString pngFilename = SkOSPath::Join(FLAGS_writePath[0], config);
                 pngFilename = SkOSPath::Join(pngFilename.c_str(), bench->getUniqueName());
                 pngFilename.append(".png");
                 write_canvas_png(targets[j], pngFilename);
@@ skipping 81 matching lines @@
 
     return 0;
 }
 
 #if !defined SK_BUILD_FOR_IOS
 int main(int argc, char** argv) {
     SkCommandLineFlags::Parse(argc, argv);
     return nanobench_main();
 }
 #endif