nanobench: Protect more against infinite loops.
BUG=skia:
R=mtklein@google.com
Author: mtklein@chromium.org
Review URL: https://codereview.chromium.org/404543002
diff --git a/bench/nanobench.cpp b/bench/nanobench.cpp
index a9862c6..59e85ed 100644
--- a/bench/nanobench.cpp
+++ b/bench/nanobench.cpp
@@ -50,6 +50,9 @@
DEFINE_string(outResultsFile, "", "If given, write results here as JSON.");
DEFINE_bool(resetGpuContext, true, "Reset the GrContext before running each bench.");
+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.");
static SkString humanize(double ms) {
@@ -62,6 +65,7 @@
#endif
return SkStringPrintf("%.3gms", ms);
}
+#define HUMANIZE(ms) humanize(ms).c_str()
static double time(int loops, Benchmark* bench, SkCanvas* canvas, SkGLContextHelper* gl) {
WallTimer timer;
@@ -90,11 +94,29 @@
return overhead / FLAGS_overheadLoops;
}
+static int clamp_loops(int loops) {
+ if (loops < 1) {
+ SkDebugf("ERROR: clamping loops from %d to 1.\n", loops);
+ return 1;
+ }
+ 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;
+ int round = 0;
do {
bench_plus_overhead = time(1, bench, canvas, NULL);
+ 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);
// Later we'll just start and stop the timer once but loop N times.
@@ -115,7 +137,7 @@
// Luckily, this also works well in practice. :)
const double numer = overhead / FLAGS_overheadGoal - overhead;
const double denom = bench_plus_overhead - overhead;
- const int loops = FLAGS_runOnce ? 1 : (int)ceil(numer / denom);
+ const int loops = clamp_loops(FLAGS_runOnce ? 1 : (int)ceil(numer / denom));
for (int i = 0; i < FLAGS_samples; i++) {
samples[i] = time(loops, bench, canvas, NULL) / loops;
@@ -151,6 +173,7 @@
// Might as well make sure we're not still timing our calibration.
SK_GL(*gl, Finish());
}
+ loops = clamp_loops(loops);
// Pretty much the same deal as the calibration: do some warmup to make
// sure we're timing steady-state pipelined frames.
@@ -281,7 +304,7 @@
fill_static_options(&log);
const double overhead = estimate_timer_overhead();
- SkDebugf("Timer overhead: %s\n", humanize(overhead).c_str());
+ SkDebugf("Timer overhead: %s\n", HUMANIZE(overhead));
SkAutoTMalloc<double> samples(FLAGS_samples);
@@ -320,7 +343,7 @@
if (loops == 0) {
SkDebugf("Unable to time %s\t%s (overhead %s)\n",
- bench->getName(), config, humanize(overhead).c_str());
+ bench->getName(), config, HUMANIZE(overhead));
continue;
}
@@ -339,22 +362,22 @@
SkDebugf("%s\t%s\n", bench->getName(), config);
} else if (FLAGS_verbose) {
for (int i = 0; i < FLAGS_samples; i++) {
- SkDebugf("%s ", humanize(samples[i]).c_str());
+ SkDebugf("%s ", HUMANIZE(samples[i]));
}
SkDebugf("%s\n", bench->getName());
} else if (FLAGS_quiet) {
if (targets.count() == 1) {
config = ""; // Only print the config if we run the same bench on more than one.
}
- SkDebugf("%s\t%s\t%s\n", humanize(stats.median).c_str(), bench->getName(), config);
+ SkDebugf("%s\t%s\t%s\n", HUMANIZE(stats.median), bench->getName(), config);
} else {
const double stddev_percent = 100 * sqrt(stats.var) / stats.mean;
SkDebugf("%d\t%s\t%s\t%s\t%s\t%.0f%%\t%s\t%s\t%s\n"
, loops
- , humanize(stats.min).c_str()
- , humanize(stats.median).c_str()
- , humanize(stats.mean).c_str()
- , humanize(stats.max).c_str()
+ , HUMANIZE(stats.min)
+ , HUMANIZE(stats.median)
+ , HUMANIZE(stats.mean)
+ , HUMANIZE(stats.max)
, stddev_percent
, stats.plot.c_str()
, config
