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runtime/pprof: output CPU profiles in pprof protobuf format

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This change buffers the entire profile and converts in one shot
in the profile writer, and could use more memory than necessary
to output protocol buffer formatted profiles. It should be
possible to convert each chunk in a stream (maybe maintaining
some minimal state to output in the end) which could save on
memory usage.

Fixes #16093

Change-Id: I946c6a2b044ae644c72c8bb2d3bd82c415b1a847
Reviewed-on: https://go-review.googlesource.com/33071
Run-TryBot: Michael Matloob <matloob@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Russ Cox <rsc@golang.org>
This commit is contained in:
Michael Matloob 2016-11-10 13:31:41 -05:00
parent 7448eb4172
commit 76f12cdaa2
5 changed files with 47 additions and 108 deletions
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63
src/runtime/pprof/pprof_test.go
View file

@ -9,6 +9,7 @@ package pprof_test
import (
"bytes"
"fmt"
"internal/pprof/profile"
"internal/testenv"
"math/big"
"os"
@ -20,7 +21,6 @@ import (
"sync"
"testing"
"time"
"unsafe"
)
func cpuHogger(f func(), dur time.Duration) {
@ -87,40 +87,17 @@ func TestCPUProfileMultithreaded(t *testing.T) {
}
func parseProfile(t *testing.T, valBytes []byte, f func(uintptr, []uintptr)) {
// Convert []byte to []uintptr.
l := len(valBytes)
if i := bytes.Index(valBytes, []byte("\nMAPPED_LIBRARIES:\n")); i >= 0 {
l = i
p, err := profile.Parse(bytes.NewReader(valBytes))
if err != nil {
t.Fatal(err)
}
l /= int(unsafe.Sizeof(uintptr(0)))
val := *(*[]uintptr)(unsafe.Pointer(&valBytes))
val = val[:l]
// 5 for the header, 3 for the trailer.
if l < 5+3 {
t.Logf("profile too short: %#x", val)
if badOS[runtime.GOOS] {
t.Skipf("ignoring failure on %s; see golang.org/issue/13841", runtime.GOOS)
return
for _, sample := range p.Sample {
count := uintptr(sample.Value[0])
stk := make([]uintptr, len(sample.Location))
for i := range sample.Location {
stk[i] = uintptr(sample.Location[i].Address)
}
t.FailNow()
}
hd, val, tl := val[:5], val[5:l-3], val[l-3:]
if hd[0] != 0 || hd[1] != 3 || hd[2] != 0 || hd[3] != 1e6/100 || hd[4] != 0 {
t.Fatalf("unexpected header %#x", hd)
}
if tl[0] != 0 || tl[1] != 1 || tl[2] != 0 {
t.Fatalf("malformed end-of-data marker %#x", tl)
}
for len(val) > 0 {
if len(val) < 2 || val[0] < 1 || val[1] < 1 || uintptr(len(val)) < 2+val[1] {
t.Fatalf("malformed profile. leftover: %#x", val)
}
f(val[0], val[2:2+val[1]])
val = val[2+val[1]:]
f(count, stk)
}
}
@ -674,3 +651,23 @@ func containsInOrder(s string, all ...string) bool {
}
return true
}
// Tests that the profiler outputs a parsable protobuf Profile profile.
func TestCPUProfileParse(t *testing.T) {
var before, after runtime.MemStats
runtime.ReadMemStats(&before)
var buf bytes.Buffer
if err := StartCPUProfile(&buf); err != nil {
t.Fatalf("Profile failed: Could not enable CPU profiling: %s\n", err)
}
time.Sleep(5 * time.Second)
StopCPUProfile()
runtime.ReadMemStats(&after)
_, err := profile.Parse(&buf)
if err != nil {
t.Fatalf("Could not parse Profile profile: %v", err)
}
}