Fix calibration loop failure condition.

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 "Benchmark.h"
@@ skipping 89 matching lines @@
     }
     if (loops > FLAGS_maxLoops) {
         SkDebugf("WARNING: clamping loops from %d to FLAGS_maxLoops, %d.\n", loops, FLAGS_maxLoops);
         return FLAGS_maxLoops;
     }
     return loops;
 }
 
 static int cpu_bench(const double overhead, Benchmark* bench, SkCanvas* canvas, double* samples) {
     // First figure out approximately how many loops of bench it takes to make overhead negligible.
-    double bench_plus_overhead;
+    double bench_plus_overhead = 0.0;
     int round = 0;
-    do {
-        bench_plus_overhead = time(1, bench, canvas, NULL);
-        if (++round == FLAGS_maxCalibrationAttempts) {
+    while (bench_plus_overhead < overhead) {
+        if (round++ == FLAGS_maxCalibrationAttempts) {
             SkDebugf("WARNING: Can't estimate loops for %s (%s vs. %s); skipping.\n",
                      bench->getName(), HUMANIZE(bench_plus_overhead), HUMANIZE(overhead));
             return 0;
         }
-    } while (bench_plus_overhead < overhead);
+        bench_plus_overhead = time(1, bench, canvas, NULL);
+    }
 
     // Later we'll just start and stop the timer once but loop N times.
     // We'll pick N to make timer overhead negligible:
     //
     //          overhead
     //  -------------------------  < FLAGS_overheadGoal
     //  overhead + N * Bench Time
     //
     // where bench_plus_overhead ≈ overhead + Bench Time.
     //
@@ skipping 410 matching lines @@
 
             const int loops =
 #if SK_SUPPORT_GPU
                 Benchmark::kGPU_Backend == targets[j]->config.backend
                 ? gpu_bench(targets[j]->gl, bench.get(), canvas, samples.get())
                 :
 #endif
                  cpu_bench(       overhead, bench.get(), canvas, samples.get());
 
             if (loops == 0) {
-                SkDebugf("Unable to time %s\t%s (overhead %s)\n",
-                         bench->getName(), config, HUMANIZE(overhead));
+                // Can't be timed.  A warning note has already been printed.
                 continue;
             }
 
             Stats stats(samples.get(), FLAGS_samples);
             log.config(config);
             benchStream.fillCurrentOptions(&log);
 #if SK_SUPPORT_GPU
             if (Benchmark::kGPU_Backend == targets[j]->config.backend) {
                 fill_gpu_options(&log, targets[j]->gl);
             }
@@ skipping 48 matching lines @@
 
     return 0;
 }
 
 #if !defined SK_BUILD_FOR_IOS
 int main(int argc, char** argv) {
     SkCommandLineFlags::Parse(argc, argv);
     return nanobench_main();
 }
 #endif