initial commit

src/jehanne/cmd/op2/op2.go

@@ -0,0 +1,107 @@
+package main
+
+import (
+	"encoding/binary"
+	"fmt"
+	"io"
+	"os"
+)
+
+/*
+first word
+high 8 bits is ee, which is an invalid address on amd64.
+next 8 bits is protocol version
+next 16 bits is unused, MBZ. Later, we can make it a packet type.
+next 16 bits is core id
+next 8 bits is unused
+next 8 bits is # words following.
+
+second word is time in ns. (soon to be tsc ticks)
+
+Third and following words are PCs, there must be at least one of them.
+*/
+type sample struct {
+	Wordcount, _    uint8
+	Coreid          uint16
+	_               uint16
+	Version, Marker uint8
+	Ns              uint64
+}
+
+type backtrace struct {
+	Pcs []uint64
+}
+
+/* the docs lie. Perl expects Count to be zero. I only wasted a day figuring this out. */
+type hdr struct {
+	Count, Slots, Format, Period, Padding uint64
+}
+
+type record struct {
+	Count, Size uint64
+	Pcs         []uint64
+}
+
+type trailer struct {
+	Zero, One, Zeroh uint64
+}
+
+func main() {
+	var s sample
+
+	r := io.Reader(os.Stdin)
+	w := io.Writer(os.Stdout)
+
+	records := make(map[string]uint64, 16384)
+	backtraces := make(map[string][]uint64, 1024)
+
+	/* ignore the documentation, it's wrong, first word must be zero.
+	 * the perl code that figures word length depends on it.
+	 */
+	hdr := hdr{0, 3, 0, 10000, 0}
+	trailer := trailer{0, 1, 0}
+	start := uint64(0)
+	end := start
+	nsamples := end
+	for binary.Read(r, binary.LittleEndian, &s) == nil {
+		numpcs := int(s.Wordcount)
+		bt := make([]uint64, numpcs)
+		binary.Read(r, binary.LittleEndian, &bt)
+		//fmt.Printf("%v\n", bt)
+		record := ""
+		/* Fix the symbols. pprof was unhappy about the 0xfffffff.
+		 * N.B. The fact that we have to mess with the bt values
+		 * is the reason we did not write a stringer for bt.
+		 */
+		for i := range bt {
+			bt[i] = bt[i] & ((uint64(1) << 32) - 1)
+			record = record + fmt.Sprintf("0x%x ", bt[i])
+		}
+		records[record]++
+		backtraces[record] = bt
+		//fmt.Printf("%v %d %d %x %v record %v\n", s, s.Wordcount, s.Coreid, s.Ns, bt, record)
+		/* how sad, once we go to ticks this gets ugly. */
+		if start == 0 {
+			start = s.Ns
+		}
+		end = s.Ns
+		nsamples++
+	}
+	/* we'll need to fix this once we go to ticks. */
+	hdr.Period = (end - start) / nsamples
+	hdr.Count = uint64(0) // !@$@!#$!@#$len(records))
+	//fmt.Printf("start %v end %v nsamples %d period %d\n", start, end, nsamples, hdr.Period)
+	binary.Write(w, binary.LittleEndian, &hdr)
+	out := make([]uint64, 2)
+	/* note that the backtrace length varies. But we're good with that. */
+	for key, v := range records {
+		bt := backtraces[key]
+		out[0] = v
+		out[1] = uint64(len(bt))
+		dump := append(out, bt...)
+		//fmt.Printf("dump %v\n", dump)
+		binary.Write(w, binary.LittleEndian, &dump)
+	}
+	binary.Write(w, binary.LittleEndian, &trailer)
+
+}