libgo: Update to weekly.2011-12-22.

From-SVN: r183150

1 files changed, 60 insertions, 11 deletions

diff --git a/libgo/go/testing/benchmark.go b/libgo/go/testing/benchmark.go
index e81e5c5..4ce6370 100644
--- a/libgo/go/testing/benchmark.go
+++ b/libgo/go/testing/benchmark.go
@@ -25,12 +25,12 @@ type InternalBenchmark struct {
 // B is a type passed to Benchmark functions to manage benchmark
 // timing and to specify the number of iterations to run.
 type B struct {
+	common
 	N         int
 	benchmark InternalBenchmark
-	ns        time.Duration
 	bytes     int64
-	start     time.Time
 	timerOn   bool
+	result    BenchmarkResult
 }
 
 // StartTimer starts timing a test.  This function is called automatically
@@ -48,7 +48,7 @@ func (b *B) StartTimer() {
 // want to measure.
 func (b *B) StopTimer() {
 	if b.timerOn {
-		b.ns += time.Now().Sub(b.start)
+		b.duration += time.Now().Sub(b.start)
 		b.timerOn = false
 	}
 }
@@ -59,7 +59,7 @@ func (b *B) ResetTimer() {
 	if b.timerOn {
 		b.start = time.Now()
 	}
-	b.ns = 0
+	b.duration = 0
 }
 
 // SetBytes records the number of bytes processed in a single operation.
@@ -70,7 +70,7 @@ func (b *B) nsPerOp() int64 {
 	if b.N <= 0 {
 		return 0
 	}
-	return b.ns.Nanoseconds() / int64(b.N)
+	return b.duration.Nanoseconds() / int64(b.N)
 }
 
 // runN runs a single benchmark for the specified number of iterations.
@@ -127,17 +127,25 @@ func roundUp(n int) int {
 	return 10 * base
 }
 
-// run times the benchmark function.  It gradually increases the number
+// run times the benchmark function in a separate goroutine.
+func (b *B) run() BenchmarkResult {
+	go b.launch()
+	<-b.signal
+	return b.result
+}
+
+// launch launches the benchmark function.  It gradually increases the number
 // of benchmark iterations until the benchmark runs for a second in order
 // to get a reasonable measurement.  It prints timing information in this form
 //		testing.BenchmarkHello	100000		19 ns/op
-func (b *B) run() BenchmarkResult {
+// launch is run by the fun function as a separate goroutine.
+func (b *B) launch() {
 	// Run the benchmark for a single iteration in case it's expensive.
 	n := 1
 	b.runN(n)
 	// Run the benchmark for at least the specified amount of time.
 	d := time.Duration(*benchTime * float64(time.Second))
-	for b.ns < d && n < 1e9 {
+	for !b.failed && b.duration < d && n < 1e9 {
 		last := n
 		// Predict iterations/sec.
 		if b.nsPerOp() == 0 {
@@ -153,7 +161,8 @@ func (b *B) run() BenchmarkResult {
 		n = roundUp(n)
 		b.runN(n)
 	}
-	return BenchmarkResult{b.N, b.ns, b.bytes}
+	b.result = BenchmarkResult{b.N, b.duration, b.bytes}
+	b.signal <- b
 }
 
 // The results of a benchmark run.
@@ -215,14 +224,32 @@ func RunBenchmarks(matchString func(pat, str string) (bool, error), benchmarks [
 		}
 		for _, procs := range cpuList {
 			runtime.GOMAXPROCS(procs)
-			b := &B{benchmark: Benchmark}
+			b := &B{
+				common: common{
+					signal: make(chan interface{}),
+				},
+				benchmark: Benchmark,
+			}
 			benchName := Benchmark.Name
 			if procs != 1 {
 				benchName = fmt.Sprintf("%s-%d", Benchmark.Name, procs)
 			}
 			fmt.Printf("%s\t", benchName)
 			r := b.run()
+			if b.failed {
+				// The output could be very long here, but probably isn't.
+				// We print it all, regardless, because we don't want to trim the reason
+				// the benchmark failed.
+				fmt.Printf("--- FAIL: %s\n%s", benchName, b.output)
+				continue
+			}
 			fmt.Printf("%v\n", r)
+			// Unlike with tests, we ignore the -chatty flag and always print output for
+			// benchmarks since the output generation time will skew the results.
+			if len(b.output) > 0 {
+				b.trimOutput()
+				fmt.Printf("--- BENCH: %s\n%s", benchName, b.output)
+			}
 			if p := runtime.GOMAXPROCS(-1); p != procs {
 				fmt.Fprintf(os.Stderr, "testing: %s left GOMAXPROCS set to %d\n", benchName, p)
 			}
@@ -230,9 +257,31 @@ func RunBenchmarks(matchString func(pat, str string) (bool, error), benchmarks [
 	}
 }
 
+// trimOutput shortens the output from a benchmark, which can be very long.
+func (b *B) trimOutput() {
+	// The output is likely to appear multiple times because the benchmark
+	// is run multiple times, but at least it will be seen. This is not a big deal
+	// because benchmarks rarely print, but just in case, we trim it if it's too long.
+	const maxNewlines = 10
+	for nlCount, j := 0, 0; j < len(b.output); j++ {
+		if b.output[j] == '\n' {
+			nlCount++
+			if nlCount >= maxNewlines {
+				b.output = append(b.output[:j], "\n\t... [output truncated]\n"...)
+				break
+			}
+		}
+	}
+}
+
 // Benchmark benchmarks a single function. Useful for creating
 // custom benchmarks that do not use gotest.
 func Benchmark(f func(b *B)) BenchmarkResult {
-	b := &B{benchmark: InternalBenchmark{"", f}}
+	b := &B{
+		common: common{
+			signal: make(chan interface{}),
+		},
+		benchmark: InternalBenchmark{"", f},
+	}
 	return b.run()
 }