runtime: malloc sampling, pprof interface

R=r
CC=golang-dev
http://codereview.appspot.com/719041

2 files changed, 103 insertions, 0 deletions

diff --git a/src/pkg/http/pprof/Makefile b/src/pkg/http/pprof/Makefile
new file mode 100644
index 000000000..e0315112f
--- /dev/null
+++ b/src/pkg/http/pprof/Makefile
@@ -0,0 +1,11 @@
+# Copyright 2010 The Go Authors. All rights reserved.
+# Use of this source code is governed by a BSD-style
+# license that can be found in the LICENSE file.
+
+include ../../../Make.$(GOARCH)
+
+TARG=http/pprof
+GOFILES=\
+	pprof.go\
+
+include ../../../Make.pkg
diff --git a/src/pkg/http/pprof/pprof.go b/src/pkg/http/pprof/pprof.go
new file mode 100644
index 000000000..38d91afbf
--- /dev/null
+++ b/src/pkg/http/pprof/pprof.go
@@ -0,0 +1,92 @@
+// Copyright 2010 The Go Authors.  All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Package pprof serves via its HTTP server runtime profiling data
+// in the format expected by the pprof visualization tool.
+// For more information about pprof, see
+// http://code.google.com/p/google-perftools/.
+//
+// The package is typically only imported for the side effect of
+// registering its HTTP handlers.
+// The handled paths all begin with /debug/pprof/.
+//
+// To use pprof, link this package into your program:
+//	import _ "http/pprof"
+//
+// Then use the pprof tool to look at the heap profile:
+//
+//	pprof http://localhost:6060/debug/pprof/heap
+//
+package pprof
+
+import (
+	"bufio"
+	"fmt"
+	"http"
+	"os"
+	"runtime"
+	"runtime/pprof"
+	"strconv"
+	"strings"
+)
+
+func init() {
+	http.Handle("/debug/pprof/cmdline", http.HandlerFunc(Cmdline))
+	http.Handle("/debug/pprof/heap", http.HandlerFunc(Heap))
+	http.Handle("/debug/pprof/symbol", http.HandlerFunc(Symbol))
+}
+
+// Cmdline responds with the running program's
+// command line, with arguments separated by NUL bytes.
+// The package initialization registers it as /debug/pprof/cmdline.
+func Cmdline(c *http.Conn, r *http.Request) {
+	c.SetHeader("content-type", "text/plain; charset=utf-8")
+	fmt.Fprintf(c, strings.Join(os.Args, "\x00"))
+}
+
+// Heap responds with the pprof-formatted heap profile.
+// The package initialization registers it as /debug/pprof/heap.
+func Heap(c *http.Conn, r *http.Request) {
+	c.SetHeader("content-type", "text/plain; charset=utf-8")
+	pprof.WriteHeapProfile(c)
+}
+
+// Symbol looks up the program counters listed in the request,
+// responding with a table mapping program counters to function names.
+// The package initialization registers it as /debug/pprof/symbol.
+func Symbol(c *http.Conn, r *http.Request) {
+	c.SetHeader("content-type", "text/plain; charset=utf-8")
+
+	// We don't know how many symbols we have, but we
+	// do have symbol information.  Pprof only cares whether
+	// this number is 0 (no symbols available) or > 0.
+	fmt.Fprintf(c, "num_symbols: 1\n")
+
+	var b *bufio.Reader
+	if r.Method == "POST" {
+		b = bufio.NewReader(r.Body)
+	} else {
+		b = bufio.NewReader(strings.NewReader(r.URL.RawQuery))
+	}
+
+	for {
+		w, err := b.ReadSlice('+')
+		if err == nil {
+			w = w[0 : len(w)-1] // trim +
+		}
+		pc, _ := strconv.Btoui64(string(w), 0)
+		if pc != 0 {
+			f := runtime.FuncForPC(uintptr(pc))
+			if f != nil {
+				fmt.Fprintf(c, "%#x %s\n", pc, f.Name())
+			}
+		}
+
+		// Wait until here to check for err; the last
+		// symbol will have an err because it doesn't end in +.
+		if err != nil {
+			break
+		}
+	}
+}