PHP 7 – What changed internally?

1. PHP 7 What changed internally? Nikita Popov

2. •Return type declarations •Scalar type declarations function startsWith(string $s1, string $s2) : bool {…}

3. 211 254 256 273 627 666 0 100 200 300 400 500 600 700 PHP 5.3 PHP 5.4 PHP 5.5 PHP 5.6 PHP 7 HHVM 3.7 Req/Sec Wordpress 4.1.1 (home, 20 c) Stolen from Rasmus

4. •Smaller data structures •Fewer allocations •Less indirection

5. zval

6. zval 5

7. NULL BOOL LONG DOUBLE STRING ARRAY OBJECT RESOURCE 5

8. NULL BOOL LONG DOUBLE STRING ARRAY OBJECT RESOURCE lval (long) dval (double) 5

9. NULL BOOL LONG DOUBLE STRING ARRAY OBJECT RESOURCE lval (long) dval (double) 5 64 bits / 8 bytes

10. NULL BOOL LONG DOUBLE STRING ARRAY OBJECT RESOURCE lval (long) dval (double) lval (long) 1 bit 5

11. NULL BOOL LONG DOUBLE STRING ARRAY OBJECT RESOURCE val (char *) len (int) A B C 0 5

12. value ty 5

13. value refcount ty 5

14. value = LONG(42) refcount = 1$i $i = 42; 5

15. value = LONG(42) refcount = 2$i $j $i = 42; $j = $i; 5

16. value = LONG(42) refcount = 3$i $j $k $i = 42; $j = $i; $k = $i; 5

17. value = LONG(42) refcount = 1 $i = 42; $j = $i; $k = $i; unset($i, $k); 5 $j

18. value = LONG(42) refcount = 0 $i = 42; $j = $i; $k = $i; unset($i, $k); unset($j); 5

19. value = LONG(42) refcount = 0 $i = 42; $j = $i; $k = $i; unset($i, $k); unset($j); free( ) 5

20. value = ARRAY refcount = 1$a $a = []; 5 [0]: (empty) [1]: (empty) [2]: (empty) …

21. value = ARRAY refcount = 2$a $a = []; $a[0] = $a; 5 [0]: [1]: (empty) [2]: (empty) …

22. value = ARRAY refcount = 1 $a = []; $a[0] = $a; unset($a); 5 [0]: [1]: (empty) [2]: (empty) …

23. value = ARRAY refcount = 1 $a = []; $a[0] = $a; unset($a); 5 [0]: [1]: (empty) [2]: (empty) … [0]: (empty) [1]: (empty) [2]: (empty) … GC root buffer

24. value = ARRAY refcount = 1 $a = []; $a[0] = $a; unset($a); 5 [0]: [1]: (empty) [2]: (empty) … [0]: [1]: (empty) [2]: (empty) … GC root buffer

25. value = ARRAY refcount = 1 gc_root $a = []; $a[0] = $a; unset($a); 5 [0]: [1]: (empty) [2]: (empty) … [0]: [1]: (empty) [2]: (empty) … GC root buffer

26. value refcount ty gc_root 5

27. size prev_size value refcount ty gc_root 5

28. size prev_size value refcount ty gc_root 5 32 bytes 16 bytes

29. value type_info (u2) 7

30. NULL BOOL LONG DOUBLE STRING ARRAY OBJECT RESOURCE 5

31. NULL BOOL LONG DOUBLE STRING ARRAY OBJECT RESOURCE 7 FALSE TRUE

32. NULL BOOL LONG DOUBLE STRING ARRAY OBJECT RESOURCE REFERENCE 7 FALSE TRUE

33. NULL FALSE TRUE LONG DOUBLE STRING ARRAY OBJECT RESOURCE REFERENCE val (char *) len (int) A B C 0 5

34. NULL FALSE TRUE LONG DOUBLE STRING ARRAY OBJECT RESOURCE REFERENCE 7 zend_string * refcount type_info hash len (size_t) A B C 0

35. NULL FALSE TRUE LONG DOUBLE STRING ARRAY OBJECT RESOURCE REFERENCE 7 zend_string * refcount type_info hash len (size_t) A B C 0 refcounted header

36. $i = 42; 7 $i value = 42 LONG

37. $i = 42; $j = $i; 7 $i value = 42 LONG $j value = 42 LONG

38. $i = 42; $j = $i; $k = $i; 7 $i value = 42 LONG $j value = 42 LONG $k value = 42 LONG

39. $s = “foobar”; 7 $s value STRING refcount = 1 type_info hash = 0x80000652FDE460BE len = 6 f o o b a r 0

40. $s = “foobar”; $t = $s; 7 $s value STRING $t value STRING refcount = 2 type_info hash = 0x80000652FDE460BE len = 6 f o o b a r 0

41. $s = “foobar”; $t = $s; $u = $s; 7 $s value STRING $t value STRING $u value STRING refcount = 3 type_info hash = 0x80000652FDE460BE len = 6 f o o b a r 0

42. 7 refcount type_info hash len (size_t) A B C 0 refcounted header

43. 7 refcount type_info hash len (size_t) A B C 0 refcounted header type flags gc_info

44. 7 refcount type_info hash len (size_t) A B C 0 refcounted header type flags gc_info INTERNED etc.

45. value type_info (u2) 7

46. value type_info (u2) 7 type type_flags const_flags

47. 7 type type_flags const_flags refcounted collectable copyable simple types string interned string array object resource reference

48. 7 type type_flags const_flags refcounted collectable copyable simple types string  interned string array  object  resource  reference 

49. 7 type type_flags const_flags refcounted collectable copyable simple types string  interned string array   object   resource  reference 

50. 7 type type_flags const_flags refcounted collectable copyable simple types string   interned string array    object   resource  reference 

51. 5 array == HashTable

52. 5 key = “foo” idx = hash(“foo”)

53. 5 key = “foo” idx = hash(“foo”) % tableSize

54. 5 [0]: (empty) [1]: (empty) [2]: (empty) [3]: (empty) “foo”

55. 5 [0]: (empty) [1]: [2]: (empty) [3]: (empty) “foo” data key “foo” zval

56. 5 [0]: (empty) [1]: [2]: (empty) [3]: (empty) “foo” data key “foo” “bar”

57. 5 [0]: (empty) [1]: [2]: (empty) [3]: (empty) “foo” data key “foo” next “bar” data key “bar” next = NULL

58. 5 [0]: (empty) [1]: [2]: (empty) [3]: (empty) “foo” data key “foo” next prev = NULL “bar” data key “bar” next = NULL prev

59. 5 data prev next key “foo” zval

60. 5 data listNext listPrev prev next key “foo” zval $a1 = [“foo” => 1, “bar” => 2]; $a2 = [“bar” => 2, “foo” => 1];

61. 5 dataPtr data listNext listPrev prev next key “foo” zval

62. 5 hash keyLen dataPtr data listNext listPrev prev next key “foo” zval

63. 7 hash key value type_info next zval

64. 7 hash key value type_info next refcount type_info hash len f o o 0 zend_string

65. 7 hash key value type_info next hash key value type_info next hash key value type_info next

66. 7 hash key value type_info next hash key value type_info next hash key value type_info next [0] [1] [2] [3]

67. 7 hash key value type_info next hash key value type_info next hash key value type_info next [0] = -1 [1] = -1 [2] = -1 [3] = -1 $a = []; numUsed = 0

68. 7 hash key value = 42 LONG next = -1 hash key value type_info next hash key value type_info next [0] = -1 [1] = 0 [2] = -1 [3] = -1 “foo” $a = []; $a[“foo”] = 42; “foo” numUsed = 1

69. 7 hash key value = 42 LONG next = -1 hash key value = 24 LONG next = -1 hash key value type_info next [0] = -1 [1] = 0 [2] = -1 [3] = 1 “foo” $a = []; $a[“foo”] = 42; $a[“bar”] = 24; “foo” “bar” “bar” numUsed = 2

70. 7 hash key value = 42 LONG next = 2 hash key value = 24 LONG next = -1 hash key value = 3.141 DOUBLE next = -1 [0] = -1 [1] = 0 [2] = -1 [3] = 1 “foo” $a = []; $a[“foo”] = 42; $a[“bar”] = 24; $a[“xyz”] = 3.141; “foo” “bar” “bar” “xyz” “xyz”

71. 7 hash key value UNDEF next = -1 hash key value = 24 LONG next = -1 hash key value = 3.141 DOUBLE next = -1 [0] = -1 [1] = 2 [2] = -1 [3] = 1 $a = []; $a[“foo”] = 42; $a[“bar”] = 24; $a[“xyz”] = 3.141; unset($a[“foo”]); “bar” “bar” “xyz” “xyz”

72. 7 hash key value type_info next hash key value type_info next [0] [1] [2] [3] [4] [5] [6] [7]

73. 7 hash key value type_info next hash key value type_info next [0] [1] [2] [3] [4] [5] [6] [7]

74. 7 hash key value type_info next hash key value type_info next [-8] [-7] [-6] [-5] [-4] [-3] [-2] [-1]

75. 7 hash key value type_info next hash key value type_info next [-8] [-7] [-6] [-5] [-4] [-3] [-2] [-1] hash data

76. 7 hash key value type_info next hash key value type_info next [-8] [-7] [-6] [-5] [-4] [-3] [-2] [-1] hash data refcount type_info data / hash pointer numUsed

77. 7 hash key value type_info next hash key value type_info next [-8] [-7] [-6] [-5] [-4] [-3] [-2] [-1] hash data refcount type_info tableMask data / hash pointer numUsed tableSize tableMask = -tableSize

78. 7 hash key value type_info next hash key value type_info next [-8] [-7] [-6] [-5] [-4] [-3] [-2] [-1] hash data refcount type_info tableMask data / hash pointer numUsed tableSize 1010111010110110 tableMask = -tableSize

79. 7 hash key value type_info next hash key value type_info next [-8] [-7] [-6] [-5] [-4] [-3] [-2] [-1] hash data refcount type_info tableMask data / hash pointer numUsed tableSize 1010111010110110 | 1111111111100000 tableMask = -tableSize

80. 7 hash key value type_info next hash key value type_info next [-8] [-7] [-6] [-5] [-4] [-3] [-2] [-1] hash data refcount type_info tableMask data / hash pointer numUsed tableSize 1010111010110110 | 1111111111100000 = 1111111111110110 = -10 tableMask = -tableSize

81. 7 hash key value type_info next hash key value type_info next [-8] [-7] [-6] [-5] [-4] [-3] [-2] [-1] hash data refcount type_info tableMask data / hash pointer numUsed numElems tableSize nextFreeElement

82. 7 hash key value type_info next hash key value type_info next [-8] [-7] [-6] [-5] [-4] [-3] [-2] [-1] hash data refcount type_info tableMask data / hash pointer numUsed numElems tableSize internalPtr nextFreeElement destructor

83. 7 hash key value type_info next hash key value type_info next [-8] [-7] [-6] [-5] [-4] [-3] [-2] [-1] hash data refcount type_info flags tableMask data / hash pointer numUsed numElems tableSize internalPtr nextFreeElement destructor flags applyCnt iterCnt

84. 7 hash key value type_info next hash key value type_info next [-8] [-7] [-6] [-5] [-4] [-3] [-2] [-1] hash data refcount type_info flags tableMask data / hash pointer numUsed numElems tableSize internalPtr nextFreeElement destructor flags applyCnt iterCnt PACKED etc.

85. 7 hash key value type_info next hash key value type_info next data refcount type_info flags tableMask data pointer numUsed numElems tableSize internalPtr nextFreeElement destructor flags applyCnt iterCnt PACKED etc.

86. 5 objects

87. 5 handle (ID) handlers zval value

88. 5 handle (ID) handlers zval value handler table object store bucket

89. 5 handle (ID) handlers zval value … read_prop() write_prop() … object store bucket

90. 5 handle (ID) handlers zval value … read_prop() write_prop() … object object store bucket actual object

91. 5 handle (ID) handlers zval value … read_prop() write_prop() … object refcount object store bucket actual object

92. 5 handle (ID) handlers zval value … read_prop() write_prop() … object dtor() free_storage() clone() refcount object store bucket actual object

93. 5 handle (ID) handlers zval value … read_prop() write_prop() … object dtor() free_storage() clone() handlers refcount gc_root object store bucket actual object

94. 5 handle (ID) handlers zval value … read_prop() write_prop() … D V ac object dtor() free_storage() clone() handlers refcount gc_root object store bucket actual object

95. 5 object store bucket standard object

96. 5 object store bucket ce standard object zend_class_entry

97. 5 object store bucket ce properties standard object zend_class_entry HashTable for dynamic properties

98. 5 object store bucket ce properties properties_table standard object zend_class_entry HashTable for dynamic properties [0] (stores $prop1) [1] (stores $prop2) [2] (stores $prop3) zval zval zval

99. 5 object store bucket ce properties properties_table guards standard object zend_class_entry HashTable for dynamic properties [0] (stores $prop1) [1] (stores $prop2) [2] (stores $prop3) zval zval zval HashTable for __get etc. guards

100. 5 object store bucket ce properties properties_table guards custom extension for internal object standard object zend_class_entry HashTable for dynamic properties [0] (stores $prop1) [1] (stores $prop2) [2] (stores $prop3) zval zval zval HashTable for __get etc. guards

101. 7 zend_object * refcount type_info ce properties zend_class_entry HashTable for dynamic properties

102. 7 zend_object * refcount type_info handle ce handlers properties zend_class_entry HashTable for dynamic properties handler table

103. 7 zend_object * refcount type_info handle ce handlers properties zend_class_entry HashTable for dynamic properties handler table object store

104. 7 zend_object * refcount type_info handle ce handlers properties value type_info value type_info value type_info zend_class_entry HashTable for dynamic properties$prop1 zval $prop2 zval $prop3 zval handler table object store

105. 7 zend_object * refcount type_info handle ce handlers properties value type_info value type_info value type_info zend_class_entry HashTable for dynamic properties HashTable for __get etc. guards guards zval $prop1 zval $prop2 zval handler table object store

106. 7 zend_object * refcount type_info handle ce handlers properties value type_info value type_info value type_info zend_class_entry HashTable for dynamic properties HashTable for __get etc. guards guards zval $prop1 zval $prop2 zval handler table object store ext. for internal objects

107. 7 zend_object * refcount type_info handle ce handlers properties value type_info value type_info value type_info zend_class_entry HashTable for dynamic properties HashTable for __get etc. guards guards zval $prop1 zval $prop2 zval handler table object store ext. for internal objects offset

108. 7 zend_object * refcount type_info handle ce handlers properties value type_info value type_info value type_info guards zval $prop1 zval $prop2 zval object store ext. for internal objects offset … handlers table offset

109. 7 zend_object * refcount type_info handle ce handlers properties value type_info value type_info value type_info guards zval $prop1 zval $prop2 zval object store ext. for internal objects offset free() dtor() clone() … handlers table offset

110. 5 references

111. value = LONG(42) refcount = 3$i $j $k $i = 42; $j = $i; $k = $i; 5

112. value = LONG(42) refcount = 2$i $k $i = 42; $j = $i; $k = $i; $k++; 5 value = LONG(43) refcount = 1 $j

113. value = LONG(42) refcount = 2$i $k $i = 42; $j = $i; $k = $i; $k++; 5 value = LONG(43) refcount = 1 $j copy-on-write (COW)

114. value = LONG(42) refcount = 3 is_ref = 1$i $j $k $i = 42; $j =& $i; $k =& $i; 5

115. value = LONG(43) refcount = 3 is_ref = 1$i $j $k $i = 42; $j =& $i; $k =& $i; $k++; 5

116. $i = 42; $j =& $i; $k =& $i; 7 $i value REFERENCE $j value REFERENCE $k value REFERENCE refcount = 3 type_info value = 42 LONG zend_reference

117. $a = range( 0,1000000); $r =& $a; 7 $a value REFERENCE $r value REFERENCE refcount = 2 type_info value ARRAY zend_reference refcount = 1 type_info … zend_array

118. $a = range( 0,1000000); $r =& $a; $v = $a; 7 $a value REFERENCE $r value REFERENCE $v value ARRAY refcount = 2 type_info value ARRAY zend_reference refcount = 2 type_info … zend_array

119. PHP 5 PHP 7 zval 32 bytes 16 bytes HashTable element 80 bytes 36 bytes (incl. zval) HashTable 72 bytes 56 bytes object 96 bytes 40 bytes

120. PHP 5 PHP 7 zval 32 bytes 16 bytes HashTable element 80 bytes 36 bytes (incl. zval) HashTable 72 bytes 56 bytes object 96 bytes 40 bytes fewer allocations less indirection

121. PHP 7 Alpha 1 June 11th

122. @nikita_ppv nikic@php.net