Source file src/runtime/pprof/proto_test.go

Documentation: runtime/pprof

     1  // Copyright 2016 The Go Authors. All rights reserved.
     2  // Use of this source code is governed by a BSD-style
     3  // license that can be found in the LICENSE file.
     4  
     5  package pprof
     6  
     7  import (
     8  	"bytes"
     9  	"encoding/json"
    10  	"fmt"
    11  	"internal/abi"
    12  	"internal/profile"
    13  	"internal/testenv"
    14  	"os"
    15  	"os/exec"
    16  	"reflect"
    17  	"runtime"
    18  	"strings"
    19  	"testing"
    20  	"unsafe"
    21  )
    22  
    23  // translateCPUProfile parses binary CPU profiling stack trace data
    24  // generated by runtime.CPUProfile() into a profile struct.
    25  // This is only used for testing. Real conversions stream the
    26  // data into the profileBuilder as it becomes available.
    27  //
    28  // count is the number of records in data.
    29  func translateCPUProfile(data []uint64, count int) (*profile.Profile, error) {
    30  	var buf bytes.Buffer
    31  	b := newProfileBuilder(&buf)
    32  	tags := make([]unsafe.Pointer, count)
    33  	if err := b.addCPUData(data, tags); err != nil {
    34  		return nil, err
    35  	}
    36  	b.build()
    37  	return profile.Parse(&buf)
    38  }
    39  
    40  // fmtJSON returns a pretty-printed JSON form for x.
    41  // It works reasonably well for printing protocol-buffer
    42  // data structures like profile.Profile.
    43  func fmtJSON(x any) string {
    44  	js, _ := json.MarshalIndent(x, "", "\t")
    45  	return string(js)
    46  }
    47  
    48  func TestConvertCPUProfileNoSamples(t *testing.T) {
    49  	// A test server with mock cpu profile data.
    50  	var buf bytes.Buffer
    51  
    52  	b := []uint64{3, 0, 500} // empty profile at 500 Hz (2ms sample period)
    53  	p, err := translateCPUProfile(b, 1)
    54  	if err != nil {
    55  		t.Fatalf("translateCPUProfile: %v", err)
    56  	}
    57  	if err := p.Write(&buf); err != nil {
    58  		t.Fatalf("writing profile: %v", err)
    59  	}
    60  
    61  	p, err = profile.Parse(&buf)
    62  	if err != nil {
    63  		t.Fatalf("profile.Parse: %v", err)
    64  	}
    65  
    66  	// Expected PeriodType and SampleType.
    67  	periodType := &profile.ValueType{Type: "cpu", Unit: "nanoseconds"}
    68  	sampleType := []*profile.ValueType{
    69  		{Type: "samples", Unit: "count"},
    70  		{Type: "cpu", Unit: "nanoseconds"},
    71  	}
    72  
    73  	checkProfile(t, p, 2000*1000, periodType, sampleType, nil, "")
    74  }
    75  
    76  func f1() { f1() }
    77  func f2() { f2() }
    78  
    79  // testPCs returns two PCs and two corresponding memory mappings
    80  // to use in test profiles.
    81  func testPCs(t *testing.T) (addr1, addr2 uint64, map1, map2 *profile.Mapping) {
    82  	switch runtime.GOOS {
    83  	case "linux", "android", "netbsd":
    84  		// Figure out two addresses from /proc/self/maps.
    85  		mmap, err := os.ReadFile("/proc/self/maps")
    86  		if err != nil {
    87  			t.Fatal(err)
    88  		}
    89  		var mappings []*profile.Mapping
    90  		id := uint64(1)
    91  		parseProcSelfMaps(mmap, func(lo, hi, offset uint64, file, buildID string) {
    92  			mappings = append(mappings, &profile.Mapping{
    93  				ID:      id,
    94  				Start:   lo,
    95  				Limit:   hi,
    96  				Offset:  offset,
    97  				File:    file,
    98  				BuildID: buildID,
    99  			})
   100  			id++
   101  		})
   102  		if len(mappings) < 2 {
   103  			// It is possible for a binary to only have 1 executable
   104  			// region of memory.
   105  			t.Skipf("need 2 or more mappings, got %v", len(mappings))
   106  		}
   107  		addr1 = mappings[0].Start
   108  		map1 = mappings[0]
   109  		addr2 = mappings[1].Start
   110  		map2 = mappings[1]
   111  	case "windows", "darwin", "ios":
   112  		addr1 = uint64(abi.FuncPCABIInternal(f1))
   113  		addr2 = uint64(abi.FuncPCABIInternal(f2))
   114  
   115  		start, end, exe, buildID, err := readMainModuleMapping()
   116  		if err != nil {
   117  			t.Fatal(err)
   118  		}
   119  
   120  		map1 = &profile.Mapping{
   121  			ID:           1,
   122  			Start:        start,
   123  			Limit:        end,
   124  			File:         exe,
   125  			BuildID:      buildID,
   126  			HasFunctions: true,
   127  		}
   128  		map2 = &profile.Mapping{
   129  			ID:           1,
   130  			Start:        start,
   131  			Limit:        end,
   132  			File:         exe,
   133  			BuildID:      buildID,
   134  			HasFunctions: true,
   135  		}
   136  	case "js", "wasip1":
   137  		addr1 = uint64(abi.FuncPCABIInternal(f1))
   138  		addr2 = uint64(abi.FuncPCABIInternal(f2))
   139  	default:
   140  		addr1 = uint64(abi.FuncPCABIInternal(f1))
   141  		addr2 = uint64(abi.FuncPCABIInternal(f2))
   142  		// Fake mapping - HasFunctions will be true because two PCs from Go
   143  		// will be fully symbolized.
   144  		fake := &profile.Mapping{ID: 1, HasFunctions: true}
   145  		map1, map2 = fake, fake
   146  	}
   147  	return
   148  }
   149  
   150  func TestConvertCPUProfile(t *testing.T) {
   151  	addr1, addr2, map1, map2 := testPCs(t)
   152  
   153  	b := []uint64{
   154  		3, 0, 500, // hz = 500
   155  		5, 0, 10, uint64(addr1 + 1), uint64(addr1 + 2), // 10 samples in addr1
   156  		5, 0, 40, uint64(addr2 + 1), uint64(addr2 + 2), // 40 samples in addr2
   157  		5, 0, 10, uint64(addr1 + 1), uint64(addr1 + 2), // 10 samples in addr1
   158  	}
   159  	p, err := translateCPUProfile(b, 4)
   160  	if err != nil {
   161  		t.Fatalf("translating profile: %v", err)
   162  	}
   163  	period := int64(2000 * 1000)
   164  	periodType := &profile.ValueType{Type: "cpu", Unit: "nanoseconds"}
   165  	sampleType := []*profile.ValueType{
   166  		{Type: "samples", Unit: "count"},
   167  		{Type: "cpu", Unit: "nanoseconds"},
   168  	}
   169  	samples := []*profile.Sample{
   170  		{Value: []int64{20, 20 * 2000 * 1000}, Location: []*profile.Location{
   171  			{ID: 1, Mapping: map1, Address: addr1},
   172  			{ID: 2, Mapping: map1, Address: addr1 + 1},
   173  		}},
   174  		{Value: []int64{40, 40 * 2000 * 1000}, Location: []*profile.Location{
   175  			{ID: 3, Mapping: map2, Address: addr2},
   176  			{ID: 4, Mapping: map2, Address: addr2 + 1},
   177  		}},
   178  	}
   179  	checkProfile(t, p, period, periodType, sampleType, samples, "")
   180  }
   181  
   182  func checkProfile(t *testing.T, p *profile.Profile, period int64, periodType *profile.ValueType, sampleType []*profile.ValueType, samples []*profile.Sample, defaultSampleType string) {
   183  	t.Helper()
   184  
   185  	if p.Period != period {
   186  		t.Errorf("p.Period = %d, want %d", p.Period, period)
   187  	}
   188  	if !reflect.DeepEqual(p.PeriodType, periodType) {
   189  		t.Errorf("p.PeriodType = %v\nwant = %v", fmtJSON(p.PeriodType), fmtJSON(periodType))
   190  	}
   191  	if !reflect.DeepEqual(p.SampleType, sampleType) {
   192  		t.Errorf("p.SampleType = %v\nwant = %v", fmtJSON(p.SampleType), fmtJSON(sampleType))
   193  	}
   194  	if defaultSampleType != p.DefaultSampleType {
   195  		t.Errorf("p.DefaultSampleType = %v\nwant = %v", p.DefaultSampleType, defaultSampleType)
   196  	}
   197  	// Clear line info since it is not in the expected samples.
   198  	// If we used f1 and f2 above, then the samples will have line info.
   199  	for _, s := range p.Sample {
   200  		for _, l := range s.Location {
   201  			l.Line = nil
   202  		}
   203  	}
   204  	if fmtJSON(p.Sample) != fmtJSON(samples) { // ignore unexported fields
   205  		if len(p.Sample) == len(samples) {
   206  			for i := range p.Sample {
   207  				if !reflect.DeepEqual(p.Sample[i], samples[i]) {
   208  					t.Errorf("sample %d = %v\nwant = %v\n", i, fmtJSON(p.Sample[i]), fmtJSON(samples[i]))
   209  				}
   210  			}
   211  			if t.Failed() {
   212  				t.FailNow()
   213  			}
   214  		}
   215  		t.Fatalf("p.Sample = %v\nwant = %v", fmtJSON(p.Sample), fmtJSON(samples))
   216  	}
   217  }
   218  
   219  var profSelfMapsTests = `
   220  00400000-0040b000 r-xp 00000000 fc:01 787766                             /bin/cat
   221  0060a000-0060b000 r--p 0000a000 fc:01 787766                             /bin/cat
   222  0060b000-0060c000 rw-p 0000b000 fc:01 787766                             /bin/cat
   223  014ab000-014cc000 rw-p 00000000 00:00 0                                  [heap]
   224  7f7d76af8000-7f7d7797c000 r--p 00000000 fc:01 1318064                    /usr/lib/locale/locale-archive
   225  7f7d7797c000-7f7d77b36000 r-xp 00000000 fc:01 1180226                    /lib/x86_64-linux-gnu/libc-2.19.so
   226  7f7d77b36000-7f7d77d36000 ---p 001ba000 fc:01 1180226                    /lib/x86_64-linux-gnu/libc-2.19.so
   227  7f7d77d36000-7f7d77d3a000 r--p 001ba000 fc:01 1180226                    /lib/x86_64-linux-gnu/libc-2.19.so
   228  7f7d77d3a000-7f7d77d3c000 rw-p 001be000 fc:01 1180226                    /lib/x86_64-linux-gnu/libc-2.19.so
   229  7f7d77d3c000-7f7d77d41000 rw-p 00000000 00:00 0
   230  7f7d77d41000-7f7d77d64000 r-xp 00000000 fc:01 1180217                    /lib/x86_64-linux-gnu/ld-2.19.so
   231  7f7d77f3f000-7f7d77f42000 rw-p 00000000 00:00 0
   232  7f7d77f61000-7f7d77f63000 rw-p 00000000 00:00 0
   233  7f7d77f63000-7f7d77f64000 r--p 00022000 fc:01 1180217                    /lib/x86_64-linux-gnu/ld-2.19.so
   234  7f7d77f64000-7f7d77f65000 rw-p 00023000 fc:01 1180217                    /lib/x86_64-linux-gnu/ld-2.19.so
   235  7f7d77f65000-7f7d77f66000 rw-p 00000000 00:00 0
   236  7ffc342a2000-7ffc342c3000 rw-p 00000000 00:00 0                          [stack]
   237  7ffc34343000-7ffc34345000 r-xp 00000000 00:00 0                          [vdso]
   238  ffffffffff600000-ffffffffff601000 r-xp 00000090 00:00 0                  [vsyscall]
   239  ->
   240  00400000 0040b000 00000000 /bin/cat
   241  7f7d7797c000 7f7d77b36000 00000000 /lib/x86_64-linux-gnu/libc-2.19.so
   242  7f7d77d41000 7f7d77d64000 00000000 /lib/x86_64-linux-gnu/ld-2.19.so
   243  7ffc34343000 7ffc34345000 00000000 [vdso]
   244  ffffffffff600000 ffffffffff601000 00000090 [vsyscall]
   245  
   246  00400000-07000000 r-xp 00000000 00:00 0
   247  07000000-07093000 r-xp 06c00000 00:2e 536754                             /path/to/gobench_server_main
   248  07093000-0722d000 rw-p 06c92000 00:2e 536754                             /path/to/gobench_server_main
   249  0722d000-07b21000 rw-p 00000000 00:00 0
   250  c000000000-c000036000 rw-p 00000000 00:00 0
   251  ->
   252  07000000 07093000 06c00000 /path/to/gobench_server_main
   253  `
   254  
   255  var profSelfMapsTestsWithDeleted = `
   256  00400000-0040b000 r-xp 00000000 fc:01 787766                             /bin/cat (deleted)
   257  0060a000-0060b000 r--p 0000a000 fc:01 787766                             /bin/cat (deleted)
   258  0060b000-0060c000 rw-p 0000b000 fc:01 787766                             /bin/cat (deleted)
   259  014ab000-014cc000 rw-p 00000000 00:00 0                                  [heap]
   260  7f7d76af8000-7f7d7797c000 r--p 00000000 fc:01 1318064                    /usr/lib/locale/locale-archive
   261  7f7d7797c000-7f7d77b36000 r-xp 00000000 fc:01 1180226                    /lib/x86_64-linux-gnu/libc-2.19.so
   262  7f7d77b36000-7f7d77d36000 ---p 001ba000 fc:01 1180226                    /lib/x86_64-linux-gnu/libc-2.19.so
   263  7f7d77d36000-7f7d77d3a000 r--p 001ba000 fc:01 1180226                    /lib/x86_64-linux-gnu/libc-2.19.so
   264  7f7d77d3a000-7f7d77d3c000 rw-p 001be000 fc:01 1180226                    /lib/x86_64-linux-gnu/libc-2.19.so
   265  7f7d77d3c000-7f7d77d41000 rw-p 00000000 00:00 0
   266  7f7d77d41000-7f7d77d64000 r-xp 00000000 fc:01 1180217                    /lib/x86_64-linux-gnu/ld-2.19.so
   267  7f7d77f3f000-7f7d77f42000 rw-p 00000000 00:00 0
   268  7f7d77f61000-7f7d77f63000 rw-p 00000000 00:00 0
   269  7f7d77f63000-7f7d77f64000 r--p 00022000 fc:01 1180217                    /lib/x86_64-linux-gnu/ld-2.19.so
   270  7f7d77f64000-7f7d77f65000 rw-p 00023000 fc:01 1180217                    /lib/x86_64-linux-gnu/ld-2.19.so
   271  7f7d77f65000-7f7d77f66000 rw-p 00000000 00:00 0
   272  7ffc342a2000-7ffc342c3000 rw-p 00000000 00:00 0                          [stack]
   273  7ffc34343000-7ffc34345000 r-xp 00000000 00:00 0                          [vdso]
   274  ffffffffff600000-ffffffffff601000 r-xp 00000090 00:00 0                  [vsyscall]
   275  ->
   276  00400000 0040b000 00000000 /bin/cat
   277  7f7d7797c000 7f7d77b36000 00000000 /lib/x86_64-linux-gnu/libc-2.19.so
   278  7f7d77d41000 7f7d77d64000 00000000 /lib/x86_64-linux-gnu/ld-2.19.so
   279  7ffc34343000 7ffc34345000 00000000 [vdso]
   280  ffffffffff600000 ffffffffff601000 00000090 [vsyscall]
   281  
   282  00400000-0040b000 r-xp 00000000 fc:01 787766                             /bin/cat with space
   283  0060a000-0060b000 r--p 0000a000 fc:01 787766                             /bin/cat with space
   284  0060b000-0060c000 rw-p 0000b000 fc:01 787766                             /bin/cat with space
   285  014ab000-014cc000 rw-p 00000000 00:00 0                                  [heap]
   286  7f7d76af8000-7f7d7797c000 r--p 00000000 fc:01 1318064                    /usr/lib/locale/locale-archive
   287  7f7d7797c000-7f7d77b36000 r-xp 00000000 fc:01 1180226                    /lib/x86_64-linux-gnu/libc-2.19.so
   288  7f7d77b36000-7f7d77d36000 ---p 001ba000 fc:01 1180226                    /lib/x86_64-linux-gnu/libc-2.19.so
   289  7f7d77d36000-7f7d77d3a000 r--p 001ba000 fc:01 1180226                    /lib/x86_64-linux-gnu/libc-2.19.so
   290  7f7d77d3a000-7f7d77d3c000 rw-p 001be000 fc:01 1180226                    /lib/x86_64-linux-gnu/libc-2.19.so
   291  7f7d77d3c000-7f7d77d41000 rw-p 00000000 00:00 0
   292  7f7d77d41000-7f7d77d64000 r-xp 00000000 fc:01 1180217                    /lib/x86_64-linux-gnu/ld-2.19.so
   293  7f7d77f3f000-7f7d77f42000 rw-p 00000000 00:00 0
   294  7f7d77f61000-7f7d77f63000 rw-p 00000000 00:00 0
   295  7f7d77f63000-7f7d77f64000 r--p 00022000 fc:01 1180217                    /lib/x86_64-linux-gnu/ld-2.19.so
   296  7f7d77f64000-7f7d77f65000 rw-p 00023000 fc:01 1180217                    /lib/x86_64-linux-gnu/ld-2.19.so
   297  7f7d77f65000-7f7d77f66000 rw-p 00000000 00:00 0
   298  7ffc342a2000-7ffc342c3000 rw-p 00000000 00:00 0                          [stack]
   299  7ffc34343000-7ffc34345000 r-xp 00000000 00:00 0                          [vdso]
   300  ffffffffff600000-ffffffffff601000 r-xp 00000090 00:00 0                  [vsyscall]
   301  ->
   302  00400000 0040b000 00000000 /bin/cat with space
   303  7f7d7797c000 7f7d77b36000 00000000 /lib/x86_64-linux-gnu/libc-2.19.so
   304  7f7d77d41000 7f7d77d64000 00000000 /lib/x86_64-linux-gnu/ld-2.19.so
   305  7ffc34343000 7ffc34345000 00000000 [vdso]
   306  ffffffffff600000 ffffffffff601000 00000090 [vsyscall]
   307  `
   308  
   309  func TestProcSelfMaps(t *testing.T) {
   310  
   311  	f := func(t *testing.T, input string) {
   312  		for tx, tt := range strings.Split(input, "\n\n") {
   313  			in, out, ok := strings.Cut(tt, "->\n")
   314  			if !ok {
   315  				t.Fatal("malformed test case")
   316  			}
   317  			if len(out) > 0 && out[len(out)-1] != '\n' {
   318  				out += "\n"
   319  			}
   320  			var buf strings.Builder
   321  			parseProcSelfMaps([]byte(in), func(lo, hi, offset uint64, file, buildID string) {
   322  				fmt.Fprintf(&buf, "%08x %08x %08x %s\n", lo, hi, offset, file)
   323  			})
   324  			if buf.String() != out {
   325  				t.Errorf("#%d: have:\n%s\nwant:\n%s\n%q\n%q", tx, buf.String(), out, buf.String(), out)
   326  			}
   327  		}
   328  	}
   329  
   330  	t.Run("Normal", func(t *testing.T) {
   331  		f(t, profSelfMapsTests)
   332  	})
   333  
   334  	t.Run("WithDeletedFile", func(t *testing.T) {
   335  		f(t, profSelfMapsTestsWithDeleted)
   336  	})
   337  }
   338  
   339  // TestMapping checks the mapping section of CPU profiles
   340  // has the HasFunctions field set correctly. If all PCs included
   341  // in the samples are successfully symbolized, the corresponding
   342  // mapping entry (in this test case, only one entry) should have
   343  // its HasFunctions field set true.
   344  // The test generates a CPU profile that includes PCs from C side
   345  // that the runtime can't symbolize. See ./testdata/mappingtest.
   346  func TestMapping(t *testing.T) {
   347  	testenv.MustHaveGoRun(t)
   348  	testenv.MustHaveCGO(t)
   349  
   350  	prog := "./testdata/mappingtest/main.go"
   351  
   352  	// GoOnly includes only Go symbols that runtime will symbolize.
   353  	// Go+C includes C symbols that runtime will not symbolize.
   354  	for _, traceback := range []string{"GoOnly", "Go+C"} {
   355  		t.Run("traceback"+traceback, func(t *testing.T) {
   356  			cmd := exec.Command(testenv.GoToolPath(t), "run", prog)
   357  			if traceback != "GoOnly" {
   358  				cmd.Env = append(os.Environ(), "SETCGOTRACEBACK=1")
   359  			}
   360  			cmd.Stderr = new(bytes.Buffer)
   361  
   362  			out, err := cmd.Output()
   363  			if err != nil {
   364  				t.Fatalf("failed to run the test program %q: %v\n%v", prog, err, cmd.Stderr)
   365  			}
   366  
   367  			prof, err := profile.Parse(bytes.NewReader(out))
   368  			if err != nil {
   369  				t.Fatalf("failed to parse the generated profile data: %v", err)
   370  			}
   371  			t.Logf("Profile: %s", prof)
   372  
   373  			hit := make(map[*profile.Mapping]bool)
   374  			miss := make(map[*profile.Mapping]bool)
   375  			for _, loc := range prof.Location {
   376  				if symbolized(loc) {
   377  					hit[loc.Mapping] = true
   378  				} else {
   379  					miss[loc.Mapping] = true
   380  				}
   381  			}
   382  			if len(miss) == 0 {
   383  				t.Log("no location with missing symbol info was sampled")
   384  			}
   385  
   386  			for _, m := range prof.Mapping {
   387  				if miss[m] && m.HasFunctions {
   388  					t.Errorf("mapping %+v has HasFunctions=true, but contains locations with failed symbolization", m)
   389  					continue
   390  				}
   391  				if !miss[m] && hit[m] && !m.HasFunctions {
   392  					t.Errorf("mapping %+v has HasFunctions=false, but all referenced locations from this lapping were symbolized successfully", m)
   393  					continue
   394  				}
   395  			}
   396  
   397  			if traceback == "Go+C" {
   398  				// The test code was arranged to have PCs from C and
   399  				// they are not symbolized.
   400  				// Check no Location containing those unsymbolized PCs contains multiple lines.
   401  				for i, loc := range prof.Location {
   402  					if !symbolized(loc) && len(loc.Line) > 1 {
   403  						t.Errorf("Location[%d] contains unsymbolized PCs and multiple lines: %v", i, loc)
   404  					}
   405  				}
   406  			}
   407  		})
   408  	}
   409  }
   410  
   411  func symbolized(loc *profile.Location) bool {
   412  	if len(loc.Line) == 0 {
   413  		return false
   414  	}
   415  	l := loc.Line[0]
   416  	f := l.Function
   417  	if l.Line == 0 || f == nil || f.Name == "" || f.Filename == "" {
   418  		return false
   419  	}
   420  	return true
   421  }
   422  
   423  // TestFakeMapping tests if at least one mapping exists
   424  // (including a fake mapping), and their HasFunctions bits
   425  // are set correctly.
   426  func TestFakeMapping(t *testing.T) {
   427  	var buf bytes.Buffer
   428  	if err := Lookup("heap").WriteTo(&buf, 0); err != nil {
   429  		t.Fatalf("failed to write heap profile: %v", err)
   430  	}
   431  	prof, err := profile.Parse(&buf)
   432  	if err != nil {
   433  		t.Fatalf("failed to parse the generated profile data: %v", err)
   434  	}
   435  	t.Logf("Profile: %s", prof)
   436  	if len(prof.Mapping) == 0 {
   437  		t.Fatal("want profile with at least one mapping entry, got 0 mapping")
   438  	}
   439  
   440  	hit := make(map[*profile.Mapping]bool)
   441  	miss := make(map[*profile.Mapping]bool)
   442  	for _, loc := range prof.Location {
   443  		if symbolized(loc) {
   444  			hit[loc.Mapping] = true
   445  		} else {
   446  			miss[loc.Mapping] = true
   447  		}
   448  	}
   449  	for _, m := range prof.Mapping {
   450  		if miss[m] && m.HasFunctions {
   451  			t.Errorf("mapping %+v has HasFunctions=true, but contains locations with failed symbolization", m)
   452  			continue
   453  		}
   454  		if !miss[m] && hit[m] && !m.HasFunctions {
   455  			t.Errorf("mapping %+v has HasFunctions=false, but all referenced locations from this lapping were symbolized successfully", m)
   456  			continue
   457  		}
   458  	}
   459  }
   460  
   461  // Make sure the profiler can handle an empty stack trace.
   462  // See issue 37967.
   463  func TestEmptyStack(t *testing.T) {
   464  	b := []uint64{
   465  		3, 0, 500, // hz = 500
   466  		3, 0, 10, // 10 samples with an empty stack trace
   467  	}
   468  	_, err := translateCPUProfile(b, 2)
   469  	if err != nil {
   470  		t.Fatalf("translating profile: %v", err)
   471  	}
   472  }
   473  

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