From: Michael Pratt Date: Thu, 21 Jul 2016 05:01:33 +0000 (-0700) Subject: cmd/pprof: instruction-level granularity in callgrind output X-Git-Tag: go1.8beta1~939 X-Git-Url: http://www.git.cypherpunks.su/?a=commitdiff_plain;h=0aadaf2ad5fa8cc1c00256840e37f422dda9689f;p=gostls13.git cmd/pprof: instruction-level granularity in callgrind output When generating callgrind format output, produce cost lines at instruction granularity. This allows visualizers supporting the callgrind format to display instruction-level profiling information. We also need to provide the object file (ob=) in order for tools to find the object file to disassemble when displaying assembly. We opportunistically group cost lines corressponding to the same function together, reducing the number of superfluous description lines. Subposition compression (relative position numbering) is also used to reduce the output size. Change-Id: Id8e960b81dc7a47ec1dfbae877521f76972431c4 Reviewed-on: https://go-review.googlesource.com/23781 Run-TryBot: Michael Pratt TryBot-Result: Gobot Gobot Reviewed-by: Raul Silvera Reviewed-by: Russ Cox --- diff --git a/src/cmd/internal/pprof/driver/driver.go b/src/cmd/internal/pprof/driver/driver.go index 782acfdf32..8f6c7e1a9c 100644 --- a/src/cmd/internal/pprof/driver/driver.go +++ b/src/cmd/internal/pprof/driver/driver.go @@ -712,8 +712,9 @@ func processFlags(p *profile.Profile, ui plugin.UI, f *flags) error { flagPeek := f.isFormat("peek") flagWebList := f.isFormat("weblist") flagList := f.isFormat("list") + flagCallgrind := f.isFormat("callgrind") - if flagDis || flagWebList { + if flagDis || flagWebList || flagCallgrind { // Collect all samples at address granularity for assembly // listing. f.flagNodeCount = newInt(0) @@ -904,16 +905,13 @@ func aggregate(prof *profile.Profile, f *flags) error { switch { case f.isFormat("proto"), f.isFormat("raw"): // No aggregation for raw profiles. - case f.isFormat("callgrind"): - // Aggregate to file/line for callgrind. - fallthrough case *f.flagLines: return prof.Aggregate(true, true, true, true, false) case *f.flagFiles: return prof.Aggregate(true, false, true, false, false) case *f.flagFunctions: return prof.Aggregate(true, true, false, false, false) - case f.isFormat("weblist"), f.isFormat("disasm"): + case f.isFormat("weblist"), f.isFormat("disasm"), f.isFormat("callgrind"): return prof.Aggregate(false, true, true, true, true) } return nil diff --git a/src/cmd/internal/pprof/report/report.go b/src/cmd/internal/pprof/report/report.go index b11ad2ab36..989665301f 100644 --- a/src/cmd/internal/pprof/report/report.go +++ b/src/cmd/internal/pprof/report/report.go @@ -355,27 +355,43 @@ func printCallgrind(w io.Writer, rpt *Report) error { g.preprocess(rpt) + fmt.Fprintln(w, "positions: instr line") fmt.Fprintln(w, "events:", o.SampleType+"("+o.OutputUnit+")") + objfiles := make(map[string]int) files := make(map[string]int) names := make(map[string]int) + + // prevInfo points to the previous nodeInfo. + // It is used to group cost lines together as much as possible. + var prevInfo *nodeInfo for _, n := range g.ns { - fmt.Fprintln(w, "fl="+callgrindName(files, n.info.file)) - fmt.Fprintln(w, "fn="+callgrindName(names, n.info.name)) + if prevInfo == nil || n.info.objfile != prevInfo.objfile || n.info.file != prevInfo.file || n.info.name != prevInfo.name { + fmt.Fprintln(w) + fmt.Fprintln(w, "ob="+callgrindName(objfiles, n.info.objfile)) + fmt.Fprintln(w, "fl="+callgrindName(files, n.info.file)) + fmt.Fprintln(w, "fn="+callgrindName(names, n.info.name)) + } + + addr := callgrindAddress(prevInfo, n.info.address) sv, _ := ScaleValue(n.flat, o.SampleUnit, o.OutputUnit) - fmt.Fprintf(w, "%d %d\n", n.info.lineno, int(sv)) + fmt.Fprintf(w, "%s %d %d\n", addr, n.info.lineno, int(sv)) // Print outgoing edges. for _, out := range sortedEdges(n.out) { c, _ := ScaleValue(out.weight, o.SampleUnit, o.OutputUnit) - count := fmt.Sprintf("%d", int(c)) callee := out.dest fmt.Fprintln(w, "cfl="+callgrindName(files, callee.info.file)) fmt.Fprintln(w, "cfn="+callgrindName(names, callee.info.name)) - fmt.Fprintln(w, "calls="+count, callee.info.lineno) - fmt.Fprintln(w, n.info.lineno, count) + fmt.Fprintf(w, "calls=%d %s %d\n", int(c), callgrindAddress(prevInfo, callee.info.address), callee.info.lineno) + // TODO: This address may be in the middle of a call + // instruction. It would be best to find the beginning + // of the instruction, but the tools seem to handle + // this OK. + fmt.Fprintf(w, "* * %d\n", int(c)) } - fmt.Fprintln(w) + + prevInfo = &n.info } return nil @@ -397,6 +413,32 @@ func callgrindName(names map[string]int, name string) string { return fmt.Sprintf("(%d) %s", id, name) } +// callgrindAddress implements the callgrind subposition compression scheme if +// possible. If prevInfo != nil, it contains the previous address. The current +// address can be given relative to the previous address, with an explicit +/- +// to indicate it is relative, or * for the same address. +func callgrindAddress(prevInfo *nodeInfo, curr uint64) string { + abs := fmt.Sprintf("%#x", curr) + if prevInfo == nil { + return abs + } + + prev := prevInfo.address + if prev == curr { + return "*" + } + + diff := int64(curr - prev) + relative := fmt.Sprintf("%+d", diff) + + // Only bother to use the relative address if it is actually shorter. + if len(relative) < len(abs) { + return relative + } + + return abs +} + // printTree prints a tree-based report in text form. func printTree(w io.Writer, rpt *Report) error { const separator = "----------------------------------------------------------+-------------" @@ -1021,7 +1063,7 @@ func newLocInfo(l *profile.Location) []nodeInfo { var objfile string if m := l.Mapping; m != nil { - objfile = filepath.Base(m.File) + objfile = m.File } if len(l.Line) == 0 { @@ -1622,7 +1664,7 @@ func (info *nodeInfo) prettyName() string { } if name = strings.TrimSpace(name); name == "" && info.objfile != "" { - name = "[" + info.objfile + "]" + name = "[" + filepath.Base(info.objfile) + "]" } return name }