cmd/pprof: heap command top and traces show different data #34236
Description
What version of Go are you using (go version)?
$ go version go version go1.11.5 linux/amd64
Does this issue reproduce with the latest release?
What operating system and processor architecture are you using (go env)?
$ go env
GOARCH="amd64"
GOBIN=""
GOCACHE="/data/tbase/.cache/go-build"
GOEXE=""
GOFLAGS=""
GOHOSTARCH="amd64"
GOHOSTOS="linux"
GOOS="linux"
GOPATH="/data/tbase/oss_compile/golang_pkg/packages:"
GOPROXY=""
GORACE=""
GOROOT="/usr/lib/golang"
GOTMPDIR=""
GOTOOLDIR="/usr/lib/golang/pkg/tool/linux_amd64"
GCCGO="gccgo"
CC="gcc"
CXX="g++"
CGO_ENABLED="1"
GOMOD=""
CGO_CFLAGS="-g -O2"
CGO_CPPFLAGS=""
CGO_CXXFLAGS="-g -O2"
CGO_FFLAGS="-g -O2"
CGO_LDFLAGS="-g -O2"
PKG_CONFIG="pkg-config"
GOGCCFLAGS="-fPIC -m64 -pthread -fmessage-length=0 -fdebug-prefix-map=/tmp/go-build502356231=/tmp/go-build -gno-record-gcc-switches" Output
What did you do?
I write a program to test pprof heap but I found someting inconsisitent.
go tool pprof http://127.0.0.1:8200/debug/pprof/heap?debug=1
Fetching profile over HTTP from http://127.0.0.1:8200/debug/pprof/heap?debug=1
Saved profile in /data/tbase/pprof/pprof.alloc_objects.alloc_space.inuse_objects.inuse_space.005.pb.gz
Type: inuse_space
No samples were found with the default sample value type.
Try "sample_index" command to analyze different sample values.
Entering interactive mode (type "help" for commands, "o" for options)
(pprof) top
Showing nodes accounting for 0, 0% of 0 total
flat flat% sum% cum cum%
(pprof) traces
Type: inuse_space
-----------+-------------------------------------------------------
bytes: 2kB
0 runtime/pprof.writeHeapInternal
runtime/pprof.writeHeap
runtime/pprof.(*Profile).WriteTo
net/http/pprof.handler.ServeHTTP
net/http/pprof.Index
net/http.HandlerFunc.ServeHTTP
net/http.(*ServeMux).ServeHTTP
net/http.serverHandler.ServeHTTP
net/http.(*conn).serve
runtime.goexit
-----------+-------------------------------------------------------
bytes: 136kB
0 compress/flate.(*compressor).init
compress/flate.NewWriter
compress/gzip.(*Writer).Write
runtime/pprof.(*profileBuilder).build
runtime/pprof.writeHeapProto
runtime/pprof.writeHeapInternal
runtime/pprof.writeHeap
runtime/pprof.(*Profile).WriteTo
net/http/pprof.handler.ServeHTTP
net/http/pprof.Index
net/http.HandlerFunc.ServeHTTP
net/http.(*ServeMux).ServeHTTP
net/http.serverHandler.ServeHTTP
net/http.(*conn).serve
runtime.goexit
-----------+-------------------------------------------------------
bytes: 8kB
0 bytes.makeSlice
bytes.(*Buffer).grow
bytes.(*Buffer).ReadFrom
io/ioutil.readAll
io/ioutil.ReadFile
runtime/pprof.(*profileBuilder).readMapping
runtime/pprof.newProfileBuilder
runtime/pprof.writeHeapProto
runtime/pprof.writeHeapInternal
runtime/pprof.writeHeap
runtime/pprof.(*Profile).WriteTo
net/http/pprof.handler.ServeHTTP
net/http/pprof.Index
net/http.HandlerFunc.ServeHTTP
net/http.(*ServeMux).ServeHTTP
net/http.serverHandler.ServeHTTP
net/http.(*conn).serve
runtime.goexit
-----------+-------------------------------------------------------
bytes: 1kB
0 sync.(*Pool).pinSlow
sync.(*Pool).pin
sync.(*Pool).Get
net/http.newBufioWriterSize
net/http.(*conn).readRequest
net/http.(*conn).serve
runtime.goexit
-----------+-------------------------------------------------------
bytes: 2.25kB
0 compress/flate.(*huffmanEncoder).generate
compress/flate.(*huffmanBitWriter).writeBlockDynamic
compress/flate.(*compressor).encSpeed
compress/flate.(*compressor).close
compress/flate.(*Writer).Close
compress/gzip.(*Writer).Close
runtime/pprof.(*profileBuilder).build
runtime/pprof.writeHeapProto
runtime/pprof.writeHeapInternal
runtime/pprof.writeHeap
runtime/pprof.(*Profile).WriteTo
net/http/pprof.handler.ServeHTTP
net/http/pprof.Index
net/http.HandlerFunc.ServeHTTP
net/http.(*ServeMux).ServeHTTP
net/http.serverHandler.ServeHTTP
net/http.(*conn).serve
runtime.goexit
-----------+-------------------------------------------------------
bytes: 648kB
0 compress/flate.NewWriter
compress/gzip.(*Writer).Write
runtime/pprof.(*profileBuilder).build
runtime/pprof.writeHeapProto
runtime/pprof.writeHeapInternal
runtime/pprof.writeHeap
runtime/pprof.(*Profile).WriteTo
net/http/pprof.handler.ServeHTTP
net/http/pprof.Index
net/http.HandlerFunc.ServeHTTP
net/http.(*ServeMux).ServeHTTP
net/http.serverHandler.ServeHTTP
net/http.(*conn).serve
runtime.goexit
-----------+-------------------------------------------------------
bytes: 1GB
0 main.Test1
main.Test
runtime.goexit
-----------+-------------------------------------------------------
(pprof)
What did you expect to see?
Top command shows nothing but traces command shows there are many memory usage.
And when I used top only to found out it did not cause that much memory.
25586_ tbase 20 0 1670.0m 36.7m 3.0m S 16.3 0.2 30:13.38 test
Here is my program.
package main
import (
_ "net/http/pprof"
"time"
"net/http"
"strconv"
"log"
)
func Test1() {
a := make([]byte,1024 *1024 * 1024)
for i := 1 ; i < 1024 * 1024 * 1024 ; i++ {
a[i] = 'c'
}
for true {
time.Sleep(10000);
}
}
func Test() {
Test1();
}
func main() {
go func() {
server_addr := ":" + strconv.Itoa(8200)
log.Println(http.ListenAndServe(server_addr, nil))
}()
go Test()
for true {
time.Sleep(10000);
}
}
How can I explain their difference?