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Addition of waitSig pprof argument to start recording on USR1 #7616

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merged 1 commit into from
Mar 5, 2021
+75 −29
Merged

Addition of waitSig pprof argument to start recording on USR1 #7616

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102 changes: 73 additions & 29 deletions go/vt/servenv/pprof.go
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Original file line number Diff line number Diff line change
Expand Up @@ -57,10 +57,11 @@ func (p profmode) filename() string {
}

type profile struct {
mode profmode
rate int
path string
quiet bool
mode profmode
rate int
path string
quiet bool
waitSig bool
}

func parseProfileFlag(pf string) (*profile, error) {
Expand Down Expand Up @@ -126,6 +127,15 @@ func parseProfileFlag(pf string) (*profile, error) {
if err != nil {
return nil, fmt.Errorf("invalid quiet flag %q: %v", fields[1], err)
}
case "waitSig":
if len(fields) == 1 {
p.waitSig = true
continue
}
p.waitSig, err = strconv.ParseBool(fields[1])
if err != nil {
return nil, fmt.Errorf("invalid waitSig flag %q: %v", fields[1], err)
}
default:
return nil, fmt.Errorf("unknown flag: %q", fields[0])
}
Expand All @@ -136,6 +146,16 @@ func parseProfileFlag(pf string) (*profile, error) {

var profileStarted uint32

func startCallback(start func()) func() {
return func() {
if atomic.CompareAndSwapUint32(&profileStarted, 0, 1) {
start()
} else {
log.Fatal("profile: Start() already called")
}
}
}

func stopCallback(stop func()) func() {
return func() {
if atomic.CompareAndSwapUint32(&profileStarted, 1, 0) {
Expand All @@ -144,14 +164,11 @@ func stopCallback(stop func()) func() {
}
}

// start begins the configured profiling process and returns a cleanup function
// that must be executed before process termination to flush the profile to disk.
// init returns a start function that begins the configured profiling process and
// returns a cleanup function that must be executed before process termination to
// flush the profile to disk.
// Based on the profiling code in github.com/pkg/profile
func (prof *profile) start() func() {
if !atomic.CompareAndSwapUint32(&profileStarted, 0, 1) {
log.Fatal("profile: Start() already called")
}

func (prof *profile) init() (start func(), stop func()) {
var (
path string
err error
Expand Down Expand Up @@ -181,16 +198,21 @@ func (prof *profile) start() func() {

switch prof.mode {
case profileCPU:
pprof.StartCPUProfile(f)
return stopCallback(func() {
start = startCallback(func() {
pprof.StartCPUProfile(f)
})
stop = stopCallback(func() {
pprof.StopCPUProfile()
f.Close()
})
return start, stop

case profileMemHeap, profileMemAllocs:
old := runtime.MemProfileRate
runtime.MemProfileRate = prof.rate
return stopCallback(func() {
start = startCallback(func() {
runtime.MemProfileRate = prof.rate
})
stop = stopCallback(func() {
tt := "heap"
if prof.mode == profileMemAllocs {
tt = "allocs"
Expand All @@ -199,49 +221,63 @@ func (prof *profile) start() func() {
f.Close()
runtime.MemProfileRate = old
})
return start, stop

case profileMutex:
runtime.SetMutexProfileFraction(prof.rate)
return stopCallback(func() {
start = startCallback(func() {
runtime.SetMutexProfileFraction(prof.rate)
})
stop = stopCallback(func() {
if mp := pprof.Lookup("mutex"); mp != nil {
mp.WriteTo(f, 0)
}
f.Close()
runtime.SetMutexProfileFraction(0)
})
return start, stop

case profileBlock:
runtime.SetBlockProfileRate(prof.rate)
return stopCallback(func() {
start = startCallback(func() {
runtime.SetBlockProfileRate(prof.rate)
})
stop = stopCallback(func() {
pprof.Lookup("block").WriteTo(f, 0)
f.Close()
runtime.SetBlockProfileRate(0)
})
return start, stop

case profileThreads:
return stopCallback(func() {
start = startCallback(func() {})
stop = stopCallback(func() {
if mp := pprof.Lookup("threadcreate"); mp != nil {
mp.WriteTo(f, 0)
}
f.Close()
})
return start, stop

case profileTrace:
if err := trace.Start(f); err != nil {
log.Fatalf("pprof: could not start trace: %v", err)
}
return stopCallback(func() {
start = startCallback(func() {
if err := trace.Start(f); err != nil {
log.Fatalf("pprof: could not start trace: %v", err)
}
})
stop = stopCallback(func() {
trace.Stop()
f.Close()
})
return start, stop

case profileGoroutine:
return stopCallback(func() {
start = startCallback(func() {})
stop = stopCallback(func() {
if mp := pprof.Lookup("goroutine"); mp != nil {
mp.WriteTo(f, 0)
}
f.Close()
})
return start, stop

default:
panic("unsupported profile mode")
Expand All @@ -255,12 +291,20 @@ func init() {
log.Fatal(err)
}
if prof != nil {
stop := prof.start()
ch := make(chan os.Signal, 1)
signal.Notify(ch, syscall.SIGUSR1)
start, stop := prof.init()

if prof.waitSig {
go func() {
<-ch
start()
}()
} else {
start()
}

go func() {
ch := make(chan os.Signal, 1)
signal.Notify(ch, syscall.SIGUSR1)

<-ch
stop()
}()
Expand Down
2 changes: 2 additions & 0 deletions go/vt/servenv/pprof_test.go
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Original file line number Diff line number Diff line change
Expand Up @@ -29,6 +29,8 @@ func TestParseProfileFlag(t *testing.T) {
{"cpu,path", nil, true},
{"cpu,path=a", &profile{mode: profileCPU, path: "a"}, false},
{"cpu,path=a/b/c/d", &profile{mode: profileCPU, path: "a/b/c/d"}, false},
{"cpu,waitSig", &profile{mode: profileCPU, waitSig: true}, false},
{"cpu,path=a/b,waitSig", &profile{mode: profileCPU, waitSig: true, path: "a/b"}, false},
}
for _, tt := range tests {
t.Run(tt.arg, func(t *testing.T) {
Expand Down