runtime/pprof: write profiles in protobuf format.

Added functions with suffix proto and stuff from pprof tool to translate
to protobuf. Done as the profile proto is more extensible than the legacy
pprof format and is pprof's preferred profile format. Large part was taken
from https://github.com/google/pprof tool. Tested by hand and compared the
result with translated by pprof tool, profiles are identical.
Fixes #16093
Change-Id: I5acdb2809cab0d16ed4694fdaa7b8ddfd68df11e
Reviewed-on: https://go-review.googlesource.com/30556
Run-TryBot: Michael Matloob <matloob@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Michael Matloob <matloob@golang.org>

1 files changed, 42 insertions, 20 deletions

diff --git a/src/runtime/pprof/mprof_test.go b/src/runtime/pprof/mprof_test.go
index 0fff9d46d9..547baada4a 100644
--- a/src/runtime/pprof/mprof_test.go
+++ b/src/runtime/pprof/mprof_test.go
@@ -6,8 +6,8 @@ package pprof_test
 
 import (
 	"bytes"
-	"fmt"
-	"regexp"
+	"math"
+	"reflect"
 	"runtime"
 	. "runtime/pprof"
 	"testing"
@@ -71,26 +71,48 @@ func TestMemoryProfiler(t *testing.T) {
 
 	memoryProfilerRun++
 
-	tests := []string{
-		fmt.Sprintf(`%v: %v \[%v: %v\] @ 0x[0-9,a-f]+ 0x[0-9,a-f]+ 0x[0-9,a-f]+ 0x[0-9,a-f]+
-#	0x[0-9,a-f]+	runtime/pprof_test\.allocatePersistent1K\+0x[0-9,a-f]+	.*/runtime/pprof/mprof_test\.go:40
-#	0x[0-9,a-f]+	runtime/pprof_test\.TestMemoryProfiler\+0x[0-9,a-f]+	.*/runtime/pprof/mprof_test\.go:63
-`, 32*memoryProfilerRun, 1024*memoryProfilerRun, 32*memoryProfilerRun, 1024*memoryProfilerRun),
-
-		fmt.Sprintf(`0: 0 \[%v: %v\] @ 0x[0-9,a-f]+ 0x[0-9,a-f]+ 0x[0-9,a-f]+ 0x[0-9,a-f]+
-#	0x[0-9,a-f]+	runtime/pprof_test\.allocateTransient1M\+0x[0-9,a-f]+	.*/runtime/pprof/mprof_test.go:21
-#	0x[0-9,a-f]+	runtime/pprof_test\.TestMemoryProfiler\+0x[0-9,a-f]+	.*/runtime/pprof/mprof_test.go:61
-`, (1<<10)*memoryProfilerRun, (1<<20)*memoryProfilerRun),
+	r := bytes.NewReader(buf.Bytes())
+	p, err := Parse(r)
+	if err != nil {
+		t.Fatalf("can't parse pprof profile: %v", err)
+	}
+	if len(p.Sample) < 3 {
+		t.Fatalf("few samples, got: %d", len(p.Sample))
+	}
+	testSample := make(map[int][]int64)
+	testSample[0] = scaleHeapSample((int64)(32*memoryProfilerRun), (int64)(1024*memoryProfilerRun), p.Period)
+	testSample[0] = append(testSample[0], testSample[0][0], testSample[0][1])
+	testSample[1] = scaleHeapSample((int64)((1<<10)*memoryProfilerRun), (int64)((1<<20)*memoryProfilerRun), p.Period)
+	testSample[1] = append([]int64{0, 0}, testSample[1][0], testSample[1][1])
+	testSample[2] = scaleHeapSample((int64)(memoryProfilerRun), (int64)((2<<20)*memoryProfilerRun), p.Period)
+	testSample[2] = append([]int64{0, 0}, testSample[2][0], testSample[2][1])
+	for _, value := range testSample {
+		found := false
+		for i := range p.Sample {
+			if reflect.DeepEqual(p.Sample[i].Value, value) {
+				found = true
+				break
+			}
+		}
+		if !found {
+			t.Fatalf("the entry did not match any sample:\n%v\n", value)
+		}
+	}
+}
 
-		fmt.Sprintf(`0: 0 \[%v: %v\] @ 0x[0-9,a-f]+ 0x[0-9,a-f]+ 0x[0-9,a-f]+ 0x[0-9,a-f]+
-#	0x[0-9,a-f]+	runtime/pprof_test\.allocateTransient2M\+0x[0-9,a-f]+	.*/runtime/pprof/mprof_test.go:27
-#	0x[0-9,a-f]+	runtime/pprof_test\.TestMemoryProfiler\+0x[0-9,a-f]+	.*/runtime/pprof/mprof_test.go:62
-`, memoryProfilerRun, (2<<20)*memoryProfilerRun),
+func scaleHeapSample(count, size, rate int64) []int64 {
+	if count == 0 || size == 0 {
+		return []int64{0, 0}
 	}
 
-	for _, test := range tests {
-		if !regexp.MustCompile(test).Match(buf.Bytes()) {
-			t.Fatalf("The entry did not match:\n%v\n\nProfile:\n%v\n", test, buf.String())
-		}
+	if rate <= 1 {
+		// if rate==1 all samples were collected so no adjustment is needed.
+		// if rate<1 treat as unknown and skip scaling.
+		return []int64{count, size}
 	}
+
+	avgSize := float64(size) / float64(count)
+	scale := 1 / (1 - math.Exp(-avgSize/float64(rate)))
+
+	return []int64{int64(float64(count) * scale), int64(float64(size) * scale)}
 }