Source file src/encoding/json/bench_test.go

     1  // Copyright 2011 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  // Large data benchmark.
     6  // The JSON data is a summary of agl's changes in the
     7  // go, webkit, and chromium open source projects.
     8  // We benchmark converting between the JSON form
     9  // and in-memory data structures.
    10  
    11  package json
    12  
    13  import (
    14  	"bytes"
    15  	"compress/gzip"
    16  	"fmt"
    17  	"internal/testenv"
    18  	"io"
    19  	"os"
    20  	"reflect"
    21  	"regexp"
    22  	"runtime"
    23  	"strings"
    24  	"sync"
    25  	"testing"
    26  )
    27  
    28  type codeResponse struct {
    29  	Tree     *codeNode `json:"tree"`
    30  	Username string    `json:"username"`
    31  }
    32  
    33  type codeNode struct {
    34  	Name     string      `json:"name"`
    35  	Kids     []*codeNode `json:"kids"`
    36  	CLWeight float64     `json:"cl_weight"`
    37  	Touches  int         `json:"touches"`
    38  	MinT     int64       `json:"min_t"`
    39  	MaxT     int64       `json:"max_t"`
    40  	MeanT    int64       `json:"mean_t"`
    41  }
    42  
    43  var codeJSON []byte
    44  var codeStruct codeResponse
    45  
    46  func codeInit() {
    47  	f, err := os.Open("testdata/code.json.gz")
    48  	if err != nil {
    49  		panic(err)
    50  	}
    51  	defer f.Close()
    52  	gz, err := gzip.NewReader(f)
    53  	if err != nil {
    54  		panic(err)
    55  	}
    56  	data, err := io.ReadAll(gz)
    57  	if err != nil {
    58  		panic(err)
    59  	}
    60  
    61  	codeJSON = data
    62  
    63  	if err := Unmarshal(codeJSON, &codeStruct); err != nil {
    64  		panic("unmarshal code.json: " + err.Error())
    65  	}
    66  
    67  	if data, err = Marshal(&codeStruct); err != nil {
    68  		panic("marshal code.json: " + err.Error())
    69  	}
    70  
    71  	if !bytes.Equal(data, codeJSON) {
    72  		println("different lengths", len(data), len(codeJSON))
    73  		for i := 0; i < len(data) && i < len(codeJSON); i++ {
    74  			if data[i] != codeJSON[i] {
    75  				println("re-marshal: changed at byte", i)
    76  				println("orig: ", string(codeJSON[i-10:i+10]))
    77  				println("new: ", string(data[i-10:i+10]))
    78  				break
    79  			}
    80  		}
    81  		panic("re-marshal code.json: different result")
    82  	}
    83  }
    84  
    85  func BenchmarkCodeEncoder(b *testing.B) {
    86  	b.ReportAllocs()
    87  	if codeJSON == nil {
    88  		b.StopTimer()
    89  		codeInit()
    90  		b.StartTimer()
    91  	}
    92  	b.RunParallel(func(pb *testing.PB) {
    93  		enc := NewEncoder(io.Discard)
    94  		for pb.Next() {
    95  			if err := enc.Encode(&codeStruct); err != nil {
    96  				b.Fatalf("Encode error: %v", err)
    97  			}
    98  		}
    99  	})
   100  	b.SetBytes(int64(len(codeJSON)))
   101  }
   102  
   103  func BenchmarkCodeEncoderError(b *testing.B) {
   104  	b.ReportAllocs()
   105  	if codeJSON == nil {
   106  		b.StopTimer()
   107  		codeInit()
   108  		b.StartTimer()
   109  	}
   110  
   111  	// Trigger an error in Marshal with cyclic data.
   112  	type Dummy struct {
   113  		Name string
   114  		Next *Dummy
   115  	}
   116  	dummy := Dummy{Name: "Dummy"}
   117  	dummy.Next = &dummy
   118  
   119  	b.RunParallel(func(pb *testing.PB) {
   120  		enc := NewEncoder(io.Discard)
   121  		for pb.Next() {
   122  			if err := enc.Encode(&codeStruct); err != nil {
   123  				b.Fatalf("Encode error: %v", err)
   124  			}
   125  			if _, err := Marshal(dummy); err == nil {
   126  				b.Fatal("Marshal error: got nil, want non-nil")
   127  			}
   128  		}
   129  	})
   130  	b.SetBytes(int64(len(codeJSON)))
   131  }
   132  
   133  func BenchmarkCodeMarshal(b *testing.B) {
   134  	b.ReportAllocs()
   135  	if codeJSON == nil {
   136  		b.StopTimer()
   137  		codeInit()
   138  		b.StartTimer()
   139  	}
   140  	b.RunParallel(func(pb *testing.PB) {
   141  		for pb.Next() {
   142  			if _, err := Marshal(&codeStruct); err != nil {
   143  				b.Fatalf("Marshal error: %v", err)
   144  			}
   145  		}
   146  	})
   147  	b.SetBytes(int64(len(codeJSON)))
   148  }
   149  
   150  func BenchmarkCodeMarshalError(b *testing.B) {
   151  	b.ReportAllocs()
   152  	if codeJSON == nil {
   153  		b.StopTimer()
   154  		codeInit()
   155  		b.StartTimer()
   156  	}
   157  
   158  	// Trigger an error in Marshal with cyclic data.
   159  	type Dummy struct {
   160  		Name string
   161  		Next *Dummy
   162  	}
   163  	dummy := Dummy{Name: "Dummy"}
   164  	dummy.Next = &dummy
   165  
   166  	b.RunParallel(func(pb *testing.PB) {
   167  		for pb.Next() {
   168  			if _, err := Marshal(&codeStruct); err != nil {
   169  				b.Fatalf("Marshal error: %v", err)
   170  			}
   171  			if _, err := Marshal(dummy); err == nil {
   172  				b.Fatal("Marshal error: got nil, want non-nil")
   173  			}
   174  		}
   175  	})
   176  	b.SetBytes(int64(len(codeJSON)))
   177  }
   178  
   179  func benchMarshalBytes(n int) func(*testing.B) {
   180  	sample := []byte("hello world")
   181  	// Use a struct pointer, to avoid an allocation when passing it as an
   182  	// interface parameter to Marshal.
   183  	v := &struct {
   184  		Bytes []byte
   185  	}{
   186  		bytes.Repeat(sample, (n/len(sample))+1)[:n],
   187  	}
   188  	return func(b *testing.B) {
   189  		for i := 0; i < b.N; i++ {
   190  			if _, err := Marshal(v); err != nil {
   191  				b.Fatalf("Marshal error: %v", err)
   192  			}
   193  		}
   194  	}
   195  }
   196  
   197  func benchMarshalBytesError(n int) func(*testing.B) {
   198  	sample := []byte("hello world")
   199  	// Use a struct pointer, to avoid an allocation when passing it as an
   200  	// interface parameter to Marshal.
   201  	v := &struct {
   202  		Bytes []byte
   203  	}{
   204  		bytes.Repeat(sample, (n/len(sample))+1)[:n],
   205  	}
   206  
   207  	// Trigger an error in Marshal with cyclic data.
   208  	type Dummy struct {
   209  		Name string
   210  		Next *Dummy
   211  	}
   212  	dummy := Dummy{Name: "Dummy"}
   213  	dummy.Next = &dummy
   214  
   215  	return func(b *testing.B) {
   216  		for i := 0; i < b.N; i++ {
   217  			if _, err := Marshal(v); err != nil {
   218  				b.Fatalf("Marshal error: %v", err)
   219  			}
   220  			if _, err := Marshal(dummy); err == nil {
   221  				b.Fatal("Marshal error: got nil, want non-nil")
   222  			}
   223  		}
   224  	}
   225  }
   226  
   227  func BenchmarkMarshalBytes(b *testing.B) {
   228  	b.ReportAllocs()
   229  	// 32 fits within encodeState.scratch.
   230  	b.Run("32", benchMarshalBytes(32))
   231  	// 256 doesn't fit in encodeState.scratch, but is small enough to
   232  	// allocate and avoid the slower base64.NewEncoder.
   233  	b.Run("256", benchMarshalBytes(256))
   234  	// 4096 is large enough that we want to avoid allocating for it.
   235  	b.Run("4096", benchMarshalBytes(4096))
   236  }
   237  
   238  func BenchmarkMarshalBytesError(b *testing.B) {
   239  	b.ReportAllocs()
   240  	// 32 fits within encodeState.scratch.
   241  	b.Run("32", benchMarshalBytesError(32))
   242  	// 256 doesn't fit in encodeState.scratch, but is small enough to
   243  	// allocate and avoid the slower base64.NewEncoder.
   244  	b.Run("256", benchMarshalBytesError(256))
   245  	// 4096 is large enough that we want to avoid allocating for it.
   246  	b.Run("4096", benchMarshalBytesError(4096))
   247  }
   248  
   249  func BenchmarkMarshalMap(b *testing.B) {
   250  	b.ReportAllocs()
   251  	m := map[string]int{
   252  		"key3": 3,
   253  		"key2": 2,
   254  		"key1": 1,
   255  	}
   256  	b.RunParallel(func(pb *testing.PB) {
   257  		for pb.Next() {
   258  			if _, err := Marshal(m); err != nil {
   259  				b.Fatal("Marshal:", err)
   260  			}
   261  		}
   262  	})
   263  }
   264  
   265  func BenchmarkCodeDecoder(b *testing.B) {
   266  	b.ReportAllocs()
   267  	if codeJSON == nil {
   268  		b.StopTimer()
   269  		codeInit()
   270  		b.StartTimer()
   271  	}
   272  	b.RunParallel(func(pb *testing.PB) {
   273  		var buf bytes.Buffer
   274  		dec := NewDecoder(&buf)
   275  		var r codeResponse
   276  		for pb.Next() {
   277  			buf.Write(codeJSON)
   278  			// hide EOF
   279  			buf.WriteByte('\n')
   280  			buf.WriteByte('\n')
   281  			buf.WriteByte('\n')
   282  			if err := dec.Decode(&r); err != nil {
   283  				b.Fatalf("Decode error: %v", err)
   284  			}
   285  		}
   286  	})
   287  	b.SetBytes(int64(len(codeJSON)))
   288  }
   289  
   290  func BenchmarkUnicodeDecoder(b *testing.B) {
   291  	b.ReportAllocs()
   292  	j := []byte(`"\uD83D\uDE01"`)
   293  	b.SetBytes(int64(len(j)))
   294  	r := bytes.NewReader(j)
   295  	dec := NewDecoder(r)
   296  	var out string
   297  	b.ResetTimer()
   298  	for i := 0; i < b.N; i++ {
   299  		if err := dec.Decode(&out); err != nil {
   300  			b.Fatalf("Decode error: %v", err)
   301  		}
   302  		r.Seek(0, 0)
   303  	}
   304  }
   305  
   306  func BenchmarkDecoderStream(b *testing.B) {
   307  	b.ReportAllocs()
   308  	b.StopTimer()
   309  	var buf bytes.Buffer
   310  	dec := NewDecoder(&buf)
   311  	buf.WriteString(`"` + strings.Repeat("x", 1000000) + `"` + "\n\n\n")
   312  	var x any
   313  	if err := dec.Decode(&x); err != nil {
   314  		b.Fatalf("Decode error: %v", err)
   315  	}
   316  	ones := strings.Repeat(" 1\n", 300000) + "\n\n\n"
   317  	b.StartTimer()
   318  	for i := 0; i < b.N; i++ {
   319  		if i%300000 == 0 {
   320  			buf.WriteString(ones)
   321  		}
   322  		x = nil
   323  		switch err := dec.Decode(&x); {
   324  		case err != nil:
   325  			b.Fatalf("Decode error: %v", err)
   326  		case x != 1.0:
   327  			b.Fatalf("Decode: got %v want 1.0", i)
   328  		}
   329  	}
   330  }
   331  
   332  func BenchmarkCodeUnmarshal(b *testing.B) {
   333  	b.ReportAllocs()
   334  	if codeJSON == nil {
   335  		b.StopTimer()
   336  		codeInit()
   337  		b.StartTimer()
   338  	}
   339  	b.RunParallel(func(pb *testing.PB) {
   340  		for pb.Next() {
   341  			var r codeResponse
   342  			if err := Unmarshal(codeJSON, &r); err != nil {
   343  				b.Fatalf("Unmarshal error: %v", err)
   344  			}
   345  		}
   346  	})
   347  	b.SetBytes(int64(len(codeJSON)))
   348  }
   349  
   350  func BenchmarkCodeUnmarshalReuse(b *testing.B) {
   351  	b.ReportAllocs()
   352  	if codeJSON == nil {
   353  		b.StopTimer()
   354  		codeInit()
   355  		b.StartTimer()
   356  	}
   357  	b.RunParallel(func(pb *testing.PB) {
   358  		var r codeResponse
   359  		for pb.Next() {
   360  			if err := Unmarshal(codeJSON, &r); err != nil {
   361  				b.Fatalf("Unmarshal error: %v", err)
   362  			}
   363  		}
   364  	})
   365  	b.SetBytes(int64(len(codeJSON)))
   366  }
   367  
   368  func BenchmarkUnmarshalString(b *testing.B) {
   369  	b.ReportAllocs()
   370  	data := []byte(`"hello, world"`)
   371  	b.RunParallel(func(pb *testing.PB) {
   372  		var s string
   373  		for pb.Next() {
   374  			if err := Unmarshal(data, &s); err != nil {
   375  				b.Fatalf("Unmarshal error: %v", err)
   376  			}
   377  		}
   378  	})
   379  }
   380  
   381  func BenchmarkUnmarshalFloat64(b *testing.B) {
   382  	b.ReportAllocs()
   383  	data := []byte(`3.14`)
   384  	b.RunParallel(func(pb *testing.PB) {
   385  		var f float64
   386  		for pb.Next() {
   387  			if err := Unmarshal(data, &f); err != nil {
   388  				b.Fatalf("Unmarshal error: %v", err)
   389  			}
   390  		}
   391  	})
   392  }
   393  
   394  func BenchmarkUnmarshalInt64(b *testing.B) {
   395  	b.ReportAllocs()
   396  	data := []byte(`3`)
   397  	b.RunParallel(func(pb *testing.PB) {
   398  		var x int64
   399  		for pb.Next() {
   400  			if err := Unmarshal(data, &x); err != nil {
   401  				b.Fatalf("Unmarshal error: %v", err)
   402  			}
   403  		}
   404  	})
   405  }
   406  
   407  func BenchmarkUnmarshalMap(b *testing.B) {
   408  	b.ReportAllocs()
   409  	data := []byte(`{"key1":"value1","key2":"value2","key3":"value3"}`)
   410  	b.RunParallel(func(pb *testing.PB) {
   411  		x := make(map[string]string, 3)
   412  		for pb.Next() {
   413  			if err := Unmarshal(data, &x); err != nil {
   414  				b.Fatalf("Unmarshal error: %v", err)
   415  			}
   416  		}
   417  	})
   418  }
   419  
   420  func BenchmarkIssue10335(b *testing.B) {
   421  	b.ReportAllocs()
   422  	j := []byte(`{"a":{ }}`)
   423  	b.RunParallel(func(pb *testing.PB) {
   424  		var s struct{}
   425  		for pb.Next() {
   426  			if err := Unmarshal(j, &s); err != nil {
   427  				b.Fatalf("Unmarshal error: %v", err)
   428  			}
   429  		}
   430  	})
   431  }
   432  
   433  func BenchmarkIssue34127(b *testing.B) {
   434  	b.ReportAllocs()
   435  	j := struct {
   436  		Bar string `json:"bar,string"`
   437  	}{
   438  		Bar: `foobar`,
   439  	}
   440  	b.RunParallel(func(pb *testing.PB) {
   441  		for pb.Next() {
   442  			if _, err := Marshal(&j); err != nil {
   443  				b.Fatalf("Marshal error: %v", err)
   444  			}
   445  		}
   446  	})
   447  }
   448  
   449  func BenchmarkUnmapped(b *testing.B) {
   450  	b.ReportAllocs()
   451  	j := []byte(`{"s": "hello", "y": 2, "o": {"x": 0}, "a": [1, 99, {"x": 1}]}`)
   452  	b.RunParallel(func(pb *testing.PB) {
   453  		var s struct{}
   454  		for pb.Next() {
   455  			if err := Unmarshal(j, &s); err != nil {
   456  				b.Fatalf("Unmarshal error: %v", err)
   457  			}
   458  		}
   459  	})
   460  }
   461  
   462  func BenchmarkTypeFieldsCache(b *testing.B) {
   463  	b.ReportAllocs()
   464  	var maxTypes int = 1e6
   465  	if testenv.Builder() != "" {
   466  		maxTypes = 1e3 // restrict cache sizes on builders
   467  	}
   468  
   469  	// Dynamically generate many new types.
   470  	types := make([]reflect.Type, maxTypes)
   471  	fs := []reflect.StructField{{
   472  		Type:  reflect.TypeFor[string](),
   473  		Index: []int{0},
   474  	}}
   475  	for i := range types {
   476  		fs[0].Name = fmt.Sprintf("TypeFieldsCache%d", i)
   477  		types[i] = reflect.StructOf(fs)
   478  	}
   479  
   480  	// clearClear clears the cache. Other JSON operations, must not be running.
   481  	clearCache := func() {
   482  		fieldCache = sync.Map{}
   483  	}
   484  
   485  	// MissTypes tests the performance of repeated cache misses.
   486  	// This measures the time to rebuild a cache of size nt.
   487  	for nt := 1; nt <= maxTypes; nt *= 10 {
   488  		ts := types[:nt]
   489  		b.Run(fmt.Sprintf("MissTypes%d", nt), func(b *testing.B) {
   490  			nc := runtime.GOMAXPROCS(0)
   491  			for i := 0; i < b.N; i++ {
   492  				clearCache()
   493  				var wg sync.WaitGroup
   494  				for j := 0; j < nc; j++ {
   495  					wg.Add(1)
   496  					go func(j int) {
   497  						for _, t := range ts[(j*len(ts))/nc : ((j+1)*len(ts))/nc] {
   498  							cachedTypeFields(t)
   499  						}
   500  						wg.Done()
   501  					}(j)
   502  				}
   503  				wg.Wait()
   504  			}
   505  		})
   506  	}
   507  
   508  	// HitTypes tests the performance of repeated cache hits.
   509  	// This measures the average time of each cache lookup.
   510  	for nt := 1; nt <= maxTypes; nt *= 10 {
   511  		// Pre-warm a cache of size nt.
   512  		clearCache()
   513  		for _, t := range types[:nt] {
   514  			cachedTypeFields(t)
   515  		}
   516  		b.Run(fmt.Sprintf("HitTypes%d", nt), func(b *testing.B) {
   517  			b.RunParallel(func(pb *testing.PB) {
   518  				for pb.Next() {
   519  					cachedTypeFields(types[0])
   520  				}
   521  			})
   522  		})
   523  	}
   524  }
   525  
   526  func BenchmarkEncodeMarshaler(b *testing.B) {
   527  	b.ReportAllocs()
   528  
   529  	m := struct {
   530  		A int
   531  		B RawMessage
   532  	}{}
   533  
   534  	b.RunParallel(func(pb *testing.PB) {
   535  		enc := NewEncoder(io.Discard)
   536  
   537  		for pb.Next() {
   538  			if err := enc.Encode(&m); err != nil {
   539  				b.Fatalf("Encode error: %v", err)
   540  			}
   541  		}
   542  	})
   543  }
   544  
   545  func BenchmarkEncoderEncode(b *testing.B) {
   546  	b.ReportAllocs()
   547  	type T struct {
   548  		X, Y string
   549  	}
   550  	v := &T{"foo", "bar"}
   551  	b.RunParallel(func(pb *testing.PB) {
   552  		for pb.Next() {
   553  			if err := NewEncoder(io.Discard).Encode(v); err != nil {
   554  				b.Fatalf("Encode error: %v", err)
   555  			}
   556  		}
   557  	})
   558  }
   559  
   560  func BenchmarkNumberIsValid(b *testing.B) {
   561  	s := "-61657.61667E+61673"
   562  	for i := 0; i < b.N; i++ {
   563  		isValidNumber(s)
   564  	}
   565  }
   566  
   567  func BenchmarkNumberIsValidRegexp(b *testing.B) {
   568  	var jsonNumberRegexp = regexp.MustCompile(`^-?(?:0|[1-9]\d*)(?:\.\d+)?(?:[eE][+-]?\d+)?$`)
   569  	s := "-61657.61667E+61673"
   570  	for i := 0; i < b.N; i++ {
   571  		jsonNumberRegexp.MatchString(s)
   572  	}
   573  }
   574  

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