internal/traceparser: provide parser that uses less space and parses …

…segments of runtime trace files

Traceparser generally takes 20-30% less space than internal/trace. The only
user of these pakcages is cmd/trace, and the new package lets it handle some
trace files that were too large. The new parser will also convert segments
of the raw trace file (e.g. the last 10 seconds) to Events. Trace files from
go 1.8 and before are not supported.

Change-Id: If83fa183246db8f75182ccd3ba8df07673c0ebd0
Reviewed-on: https://go-review.googlesource.com/c/137635
Run-TryBot: Peter Weinberger <pjw@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Hyang-Ah Hana Kim <hyangah@gmail.com>

misc/nacl/README

@@ -26,7 +26,7 @@ scheme.
 # Download NaCl
 
 Download nacl_sdk.zip file from
-	https://developers.google.com/native-client/dev/sdk/download
+	https://developer.chrome.com/native-client/sdk/download
 and unpack it. I chose /opt/nacl_sdk.
 
 # Update
@@ -37,7 +37,7 @@ sdk. These are released every 6-8 weeks, in line with Chrome releases.
 	% cd /opt/nacl_sdk
 	% ./naclsdk update
 
-At this time pepper_40 is the stable version. The NaCl port needs at least pepper_39
+At this time pepper_49 is the stable version. The NaCl port needs at least pepper_39
 to work. If naclsdk downloads a later version, please adjust accordingly.
 
 The cmd/go helper scripts expect that the loaders sel_ldr_{x86_{32,64},arm} and

misc/nacl/testzip.proto

@@ -154,6 +154,9 @@ go	src=..
 			trace
 				testdata
 					+
+			traceparser
+				testdata
+					+
 		io
 			+
 		mime

src/go/build/deps_test.go

@@ -272,6 +272,8 @@ var pkgDeps = map[string][]string{
 	"internal/goroot":                {"L4", "OS"},
 	"internal/singleflight":          {"sync"},
 	"internal/trace":                 {"L4", "OS"},
+	"internal/traceparser":           {"L4", "internal/traceparser/filebuf"},
+	"internal/traceparser/filebuf":   {"L4", "OS"},
 	"math/big":                       {"L4"},
 	"mime":                           {"L4", "OS", "syscall", "internal/syscall/windows/registry"},
 	"mime/quotedprintable":           {"L4"},

src/internal/traceparser/consistent.go

@@ -0,0 +1,313 @@
+// Copyright 2018 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 traceparser
+
+// postProcess is a final check of consistency, and if all is well,
+// adds links to Events
+
+import (
+	"fmt"
+)
+
+type gStatus int
+
+const (
+	gDead gStatus = iota
+	gRunnable
+	gRunning
+	gWaiting
+)
+
+// This code is copied from internal/trace/parser.go. With greater understanding it could be
+// simplified. Sets ev.P for GCStart, and set various Link fields
+func (p *Parsed) postProcess(events []*Event) error {
+	type gdesc struct {
+		state        gStatus
+		ev           *Event
+		evStart      *Event
+		evCreate     *Event
+		evMarkAssist *Event
+	}
+	type pdesc struct {
+		running bool
+		g       uint64
+		evSTW   *Event
+		evSweep *Event
+	}
+
+	gs := make(map[uint64]gdesc)
+	ps := make(map[int]pdesc)
+	tasks := make(map[uint64]*Event)           // task id to task creation events
+	activeRegions := make(map[uint64][]*Event) // goroutine id to stack of spans
+	gs[0] = gdesc{state: gRunning}
+	var evGC, evSTW *Event
+
+	checkRunning := func(pd pdesc, g gdesc, ev *Event, allowG0 bool) error {
+		if g.state != gRunning {
+			return fmt.Errorf("saw %v, but g %d is not running", ev, ev.G)
+		}
+		if pd.g != ev.G {
+			return fmt.Errorf("saw %v, but it's P is running %d, not %d", ev, pd.g, ev.G)
+		}
+		if !allowG0 && ev.G == 0 {
+			return fmt.Errorf("saw %v with unexpected g==0", ev)
+		}
+		return nil
+	}
+	for i, ev := range events {
+		g := gs[ev.G]
+		px := ps[int(ev.P)]
+		switch ev.Type {
+		case EvProcStart:
+			if px.running {
+				return fmt.Errorf("%d: running before start %s", i, ev)
+			}
+			px.running = true
+		case EvProcStop:
+			if !px.running {
+				return fmt.Errorf("%d: p %d not running %s", i, ev.P, ev)
+			}
+			if px.g != 0 {
+				return fmt.Errorf("p %d is running a goroutine %s", ev.P, ev)
+			}
+			px.running = false
+		case EvGCStart:
+			if evGC != nil {
+				return fmt.Errorf("GC already running %s, was %s", ev, evGC)
+			}
+			evGC = ev
+			// Attribute this to the global GC state.
+			ev.P = GCP
+		case EvGCDone:
+			if evGC == nil {
+				return fmt.Errorf("%d:%s bogus GC end", i, ev)
+			}
+			evGC.Link = ev
+			evGC = nil
+		case EvGCSTWStart:
+			evp := &evSTW
+			if p.Version < 1010 {
+				// Before 1.10, EvGCSTWStart was per-P.
+				evp = &px.evSTW
+			}
+			if *evp != nil {
+				return fmt.Errorf("STW %s still running at %s", *evp, ev)
+			}
+			*evp = ev
+		case EvGCSTWDone:
+			evp := &evSTW
+			if p.Version < 1010 {
+				// Before 1.10, EvGCSTWDone was per-P.
+				evp = &px.evSTW
+			}
+			if *evp == nil {
+				return fmt.Errorf("%d: no STW running %s", i, ev)
+			}
+			(*evp).Link = ev
+			*evp = nil
+		case EvGCMarkAssistStart:
+			if g.evMarkAssist != nil {
+				return fmt.Errorf("%d: MarkAssist %s is still running at %s",
+					i, g.evMarkAssist, ev)
+			}
+			g.evMarkAssist = ev
+		case EvGCMarkAssistDone:
+			// Unlike most events, mark assists can be in progress when a
+			// goroutine starts tracing, so we can't report an error here.
+			if g.evMarkAssist != nil {
+				g.evMarkAssist.Link = ev
+				g.evMarkAssist = nil
+			}
+		case EvGCSweepStart:
+			if px.evSweep != nil {
+				return fmt.Errorf("sweep not done %d: %s", i, ev)
+			}
+			px.evSweep = ev
+		case EvGCSweepDone:
+			if px.evSweep == nil {
+				return fmt.Errorf("%d: no sweep happening %s", i, ev)
+			}
+			px.evSweep.Link = ev
+			px.evSweep = nil
+		case EvGoWaiting:
+			if g.state != gRunnable {
+				return fmt.Errorf("not runnable before %d:%s", i, ev)
+			}
+			g.state = gWaiting
+			g.ev = ev
+		case EvGoInSyscall:
+			if g.state != gRunnable {
+				return fmt.Errorf("not runnable before %d:%s", i, ev)
+			}
+			g.state = gWaiting
+			g.ev = ev
+		case EvGoCreate:
+			if err := checkRunning(px, g, ev, true); err != nil {
+				return err
+			}
+			if _, ok := gs[ev.Args[0]]; ok {
+				return fmt.Errorf("%d: already exists %s", i, ev)
+			}
+			gs[ev.Args[0]] = gdesc{state: gRunnable, ev: ev, evCreate: ev}
+		case EvGoStart, EvGoStartLabel:
+			if g.state != gRunnable {
+				return fmt.Errorf("not runnable before start %d:%s %+v", i, ev, g)
+			}
+			if px.g != 0 {
+				return fmt.Errorf("%d: %s has p running %d already %v", i, ev, px.g, px)
+			}
+			g.state = gRunning
+			g.evStart = ev
+			px.g = ev.G
+			if g.evCreate != nil {
+				if p.Version < 1007 {
+					// +1 because symbolizer expects return pc.
+					//PJW: aren't doing < 1007. ev.stk = []*Frame{{PC: g.evCreate.args[1] + 1}}
+				} else {
+					ev.StkID = uint32(g.evCreate.Args[1])
+				}
+				g.evCreate = nil
+			}
+
+			if g.ev != nil {
+				g.ev.Link = ev
+				g.ev = nil
+			}
+		case EvGoEnd, EvGoStop:
+			if err := checkRunning(px, g, ev, false); err != nil {
+				return fmt.Errorf("%d: %s", i, err)
+			}
+			g.evStart.Link = ev
+			g.evStart = nil
+			g.state = gDead
+			px.g = 0
+
+			if ev.Type == EvGoEnd { // flush all active Regions
+				spans := activeRegions[ev.G]
+				for _, s := range spans {
+					s.Link = ev
+				}
+				delete(activeRegions, ev.G)
+			}
+		case EvGoSched, EvGoPreempt:
+			if err := checkRunning(px, g, ev, false); err != nil {
+				return err
+			}
+			g.state = gRunnable
+			g.evStart.Link = ev
+			g.evStart = nil
+			px.g = 0
+			g.ev = ev
+		case EvGoUnblock:
+			if g.state != gRunning { // PJW, error message
+				return fmt.Errorf("Event %d (%s) is not running at unblock %s", i, ev, g.state)
+
+			}
+			if ev.P != TimerP && px.g != ev.G {
+				// PJW: do better here.
+				return fmt.Errorf("%d: %s p %d is not running g", i, ev, px.g)
+			}
+			g1 := gs[ev.Args[0]]
+			if g1.state != gWaiting {
+				return fmt.Errorf("g %v is not waiting before unpark i=%d g1=%v %s",
+					ev.Args[0], i, g1, ev)
+			}
+			if g1.ev != nil && g1.ev.Type == EvGoBlockNet && ev.P != TimerP {
+				ev.P = NetpollP
+			}
+			if g1.ev != nil {
+				g1.ev.Link = ev
+			}
+			g1.state = gRunnable
+			g1.ev = ev
+			gs[ev.Args[0]] = g1
+		case EvGoSysCall:
+			if err := checkRunning(px, g, ev, false); err != nil {
+				return err
+			}
+			g.ev = ev
+		case EvGoSysBlock:
+			if err := checkRunning(px, g, ev, false); err != nil {
+				return err
+			}
+			g.state = gWaiting
+			g.evStart.Link = ev
+			g.evStart = nil
+			px.g = 0
+		case EvGoSysExit:
+			if g.state != gWaiting {
+				return fmt.Errorf("not waiting when %s", ev)
+			}
+			if g.ev != nil && g.ev.Type == EvGoSysCall {
+				g.ev.Link = ev
+			}
+			g.state = gRunnable
+			g.ev = ev
+		case EvGoSleep, EvGoBlock, EvGoBlockSend, EvGoBlockRecv,
+			EvGoBlockSelect, EvGoBlockSync, EvGoBlockCond, EvGoBlockNet, EvGoBlockGC:
+			if err := checkRunning(px, g, ev, false); err != nil {
+				return err
+			}
+			g.state = gWaiting
+			g.ev = ev
+			g.evStart.Link = ev
+			g.evStart = nil
+			px.g = 0
+		case EvUserTaskCreate:
+			taskid := ev.Args[0]
+			if prevEv, ok := tasks[taskid]; ok {
+				return fmt.Errorf("task id conflicts (id:%d), %q vs %q", taskid, ev, prevEv)
+			}
+			tasks[ev.Args[0]] = ev
+		case EvUserTaskEnd:
+			if prevEv, ok := tasks[ev.Args[0]]; ok {
+				prevEv.Link = ev
+				ev.Link = prevEv
+			}
+		case EvUserRegion:
+			mode := ev.Args[1]
+			spans := activeRegions[ev.G]
+			if mode == 0 { // span start
+				activeRegions[ev.G] = append(spans, ev) // push
+			} else if mode == 1 { // span end
+				n := len(spans)
+				if n > 0 { // matching span start event is in the trace.
+					s := spans[n-1]
+					if s.Args[0] != ev.Args[0] || s.SArgs[0] != ev.SArgs[0] { // task id, span name mismatch
+						return fmt.Errorf("misuse of span in goroutine %d: span end %q when the inner-most active span start event is %q",
+							ev.G, ev, s)
+					}
+					// Link span start event with span end event
+					s.Link = ev
+					ev.Link = s
+
+					if n > 1 {
+						activeRegions[ev.G] = spans[:n-1]
+					} else {
+						delete(activeRegions, ev.G)
+					}
+				}
+			} else {
+				return fmt.Errorf("invalid user region, mode: %q", ev)
+			}
+		}
+		gs[ev.G] = g
+		ps[int(ev.P)] = px
+	}
+	return nil
+}
+func (g gStatus) String() string {
+	switch g {
+	case gDead:
+		return "gDead"
+	case gRunnable:
+		return "gRunnable"
+	case gRunning:
+		return "gRunning"
+	case gWaiting:
+		return "gWaiting"
+	}
+	return fmt.Sprintf("gStatus?%d", g)
+}