Insert swapbuffers into GPU benchmarks.

bench/benchmain.cpp

 
 /*
  * Copyright 2011 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #if SK_SUPPORT_GPU
 #include "GrContext.h"
@@ skipping 547 matching lines @@
             if (kGPU_Backend == config.backend) {
                 contextHelper = gContextFactory.getGLContext(config.contextType);
             }
             BenchTimer timer(contextHelper);
 #else
             BenchTimer timer;
 #endif
 
             double previous = std::numeric_limits<double>::infinity();
             bool converged = false;
-            bench->setLoops(0);
+
+            // variables used to compute loopsPerFrame
+            double frameIntervalTime = 0.0f;
+            int frameIntervalTotalLoops = 0;
+
+            bool frameIntervalComputed = false;
+            int loopsPerFrame = 0;
+            int loopsPerIter = 0;
             if (FLAGS_verbose) { SkDebugf("%s %s: ", bench->getName(), config.name); }
             do {
-                // Ramp up 1 -> 4 -> 16 -> ... -> ~1 billion.
-                const int loops = bench->getLoops();
-                if (loops >= (1<<30) || timer.fWall > FLAGS_maxMs) {
+                // Ramp up 1 -> 2 -> 4 -> 8 -> 16 -> ... -> ~1 billion.
+                loopsPerIter = (loopsPerIter == 0) ? 1 : loopsPerIter * 2;
+                if (loopsPerIter >= (1<<30) || timer.fWall > FLAGS_maxMs) {
                     // If you find it takes more than a billion loops to get up to 20ms of runtime,
                     // you've got a computer clocked at several THz or have a broken benchmark.  ;)
                     //     "1B ought to be enough for anybody."
                     logger.logError(SkStringPrintf(
-                        "Can't get %s %s to converge in %dms.\n",
-                         bench->getName(), config.name, FLAGS_maxMs));
+                        "\nCan't get %s %s to converge in %dms (%d loops)",
+                         bench->getName(), config.name, FLAGS_maxMs, loopsPerIter));
                     break;
                 }
-                bench->setLoops(loops == 0 ? 1 : loops * 2);
 
                 if ((benchMode == kRecord_BenchMode || benchMode == kPictureRecord_BenchMode)) {
                     // Clear the recorded commands so that they do not accumulate.
                     canvas.reset(recordTo.beginRecording(dim.fX, dim.fY, kRecordFlags));
                 }
 
                 timer.start();
                 if (NULL != canvas) {
                     canvas->save();
                 }
-                if (benchMode == kPictureRecord_BenchMode) {
-                    recordFrom.draw(canvas);
-                } else {
-                    bench->draw(canvas);
-                }
 
-                if (kDeferredSilent_BenchMode == benchMode) {
-                    static_cast<SkDeferredCanvas*>(canvas.get())->silentFlush();
-                } else if (NULL != canvas) {
-                    canvas->flush();
+                // Inner loop that allows us to break the run into smaller
+                // chunks (e.g. frames). This is especially useful for the GPU
+                // as we can flush and/or swap buffers to keep the GPU from
+                // queuing up too much work.
+                for (int loopCount = loopsPerIter; loopCount > 0; ) {
+                    if (frameIntervalComputed && loopCount > loopsPerFrame) {
+                        bench->setLoops(loopsPerFrame);
+                        loopCount -= loopsPerFrame;
+                    } else {
+                        bench->setLoops(loopCount);
+                        loopCount = 0;
+                    }
+
+                    if (benchMode == kPictureRecord_BenchMode) {
+                        recordFrom.draw(canvas);
+                    } else {
+                        bench->draw(canvas);
+                    }
+
+                    if (kDeferredSilent_BenchMode == benchMode) {
+                        static_cast<SkDeferredCanvas*>(canvas.get())->silentFlush();
+                    } else if (NULL != canvas) {
+                        canvas->flush();
+                    }
+
+#if SK_SUPPORT_GPU
+                    // swap drawing buffers on each frame to prevent the GPU
+                    // from queuing up too much work
+                    if (NULL != glContext) {
+                        glContext->swapBuffers();
+                    }
+#endif
                 }
 
                 if (NULL != canvas) {
                     canvas->restore();
                 }
 
 
                 // Stop truncated timers before GL calls complete, and stop the full timers after.
                 timer.truncatedEnd();
 #if SK_SUPPORT_GPU
                 if (NULL != glContext) {
                     context->flush();
                     SK_GL(*glContext, Finish());
                 }
 #endif
                 timer.end();
-                const double current = timer.fWall / bench->getLoops();
+
+#if SK_SUPPORT_GPU
+                // currently we only setup the frame interval for the GPU

[mtklein, 2013/10/10 15:01:05]

Any particular reason?  Just to keep the CL focused on GPU?

+                if (!frameIntervalComputed && NULL != glContext) {
+                    frameIntervalTime += timer.fWall;
+                    frameIntervalTotalLoops += loopsPerIter;
+                    if (frameIntervalTime >= FLAGS_minMs) {
+                        frameIntervalComputed = true;
+                        loopsPerFrame =
+                            ((double)frameIntervalTotalLoops / frameIntervalTime) * FLAGS_minMs;
+                        if (loopsPerFrame < 1) {
+                            loopsPerFrame = 1;
+                        }
+//                        SkDebugf("  %s has %d loops in %f ms (normalized to %d)\n",
+//                                 bench->getName(), frameIntervalTotalLoops,
+//                                 timer.fWall, loopsPerFrame);
+                    }
+                }
+#endif
+                const double current = timer.fWall / loopsPerIter;
                 if (FLAGS_verbose && current > previous) { SkDebugf("↑"); }
                 if (FLAGS_verbose) { SkDebugf("%.3g ", current); }
                 converged = HasConverged(previous, current, timer.fWall);
                 previous = current;
             } while (!kIsDebug && !converged);
             if (FLAGS_verbose) { SkDebugf("\n"); }
 
             if (FLAGS_outDir.count() && kNonRendering_Backend != config.backend) {
                 saveFile(bench->getName(),
                          config.name,
                          FLAGS_outDir[0],
                          device->accessBitmap(false));
             }
 
             if (kIsDebug) {
                 // Let's not mislead ourselves by looking at Debug build bench times!
                 continue;
             }
 
             // Normalize to ms per 1000 iterations.
-            const double normalize = 1000.0 / bench->getLoops();
+            const double normalize = 1000.0 / loopsPerIter;
             const struct { char shortName; const char* longName; double ms; } times[] = {
                 {'w', "msecs",  normalize * timer.fWall},
                 {'W', "Wmsecs", normalize * timer.fTruncatedWall},
                 {'c', "cmsecs", normalize * timer.fCpu},
                 {'C', "Cmsecs", normalize * timer.fTruncatedCpu},
                 {'g', "gmsecs", normalize * timer.fGpu},
             };
 
             SkString result;
             result.appendf("   %s:", config.name);
@@ skipping 13 matching lines @@
     gContextFactory.destroyContexts();
 #endif
     return 0;
 }
 
 #if !defined(SK_BUILD_FOR_IOS) && !defined(SK_BUILD_FOR_NACL)
 int main(int argc, char * const argv[]) {
     return tool_main(argc, (char**) argv);
 }
 #endif