PHP Performance SfLive 2010

PHP Performances De Cock Xavier

Who am I?
PECL Developer
BBCode extension
Various in house extensions
Swiftmailer contributor
Started to work on swiftmailer for performance issues.

What is PHP ?
Scripting langage
Scripting engine
Zend Engine
Extensions providing functionalities

Zend Engine
Memory representation of datas
Source code compilation to Opcode
Opcode Handling
Memory management

Meet The Zval
Zval is the way ZE Stores values

Benefits
The Zval use
Copy on write
Automatic type conversion
Automatic garbage collection when ref_count is 0
As of PHP 5.3 Cyclic garbage collector

Zval Examples <?php $a = 41 ; /* Context ("a" => Zval_1); * Zval_1 {ref_count:1, value:41, type:LONG}; */ $b = $a ; /* Context ("a" => Zval_1, "b" => Zval_1); * Zval_1 {ref_count:2, value:41, type:LONG}; */ $b ++ ; /* Context ("a"=> Zval_1, "b" => Zval_2); * Zval_1 {ref_count:1, value:41, type:LONG}; * Zval_2 {ref_count:1, value:42, type:LONG}; */ $b .= ", The answer ..." ; /* Context ("a"=> Zval_1, "b" => Zval_3); * Zval_1 {ref_count:1, value:41, type:LONG}; * Zval_2 {ref_count:0, value:42, type:LONG}; // Freed * Zval_3 {ref_count:1, value:"42, The answer ...", type:STRING}; */

Don't try to outsmart ZE
Working by reference will usually make you waste memory as it can trigger more easily the copy on write
< ?php $a = 1 ; /* Zval {val:1; ref_count:1; is_ref:f} */ $b = & $a ; /* Zval {val:1; ref_count:2; is_ref: t } */ print ( $b ); /* This is a pass by value function, so, * what's send to print is : * Zval2 {val:1 ref_count:1; is_ref:f } */

Zend Op
Opcode is the “machine langage” of ZE
What's in a zend_op
OpCode
Op1
Op2
Metas (line n°, handler, result, ...)

Opcode examples <?php echo "Hello", " ", "World"; filename: /home/xavier/- function name: (null) number of ops: 5 compiled vars: none line # op operands --------------------------------------------- 2 0 ECHO OP1[ 'Hello' ] 1 ECHO OP1[ ' ' ] 2 ECHO OP1[ 'World' ] 4 3 RETURN OP1[ 1 ] 4* ZEND_HANDLE_EXCEPTION

Opcode examples <?php echo "Hello"." "."World"; filename: /home/xavier/- function name: (null) number of ops: 5 compiled vars: none line # op return operands --------------------------------------- 2 0 CONCAT RES[ ~0 ] OP1[ 'Hello' ] OP2[ '+' ] 1 CONCAT RES[ ~1 ] OP1[ ~0 ] OP2[ 'World' ] 2 ECHO OP1[ ~1 ] 3 3 RETURN OP1[ 1 ] 4* ZEND_HANDLE_EXCEPTION

Hash Tables
Everythings basically stays in an hash table
Symbol Tables (Local / global Variables)
Arrays
Object Properties
Ini Directives, included Files
Classes, Functions, Constants

Hash Tables
Pros:
2 quick access patterns
Get value by key
Table Traversal nest / previous item
Count is a fast operation
Cons:
Not able to browse by value

Garbage collector
PHP 5.3 includes a Garbage collector that break reference cycle.
PHP 5.2 does not include a GC
Avoid creating cycles
Break them before unset
Try to keep in mind what can hold ref
Keep in mind what handle ref:
Closures, Callback, Ressources, ...

SwiftMailer Examples Implementation 1 foreach ( unpack ('C*' , $bytes ) as $byte ) // Convert String to int array { $this -> _array [] = pack ('C' , $byte ); // Function Call in tight loop } filename: /home/xavier/Bureau/php-5.3.1/ext/- function name: (null) number of ops: 17 compiled vars: !0 = $bytes, !1 = $byte line # op return operands ----------------------------------------------- 2 0 SEND_VAL OP1[ 'C*' ] 1 SEND_VAR OP1[ !0 ] 2 DO_FCALL OP1[ 'unpack' ] 3 FE_RESET RES[ $1 ] OP1[ $0 ] OP2[ ->14 ] 4 FE_FETCH RES[ $2 ] OP1[ $1 ] OP2[ ->14 ] 5 ZEND_OP_DATA RES[ UNUSED ] OP1[ UNUSED ] OP2[ UNUSED ] 6 ASSIGN OP1[ !1 ] OP2[ $2 ] 4 7 SEND_VAL OP1[ 'C' ] 8 SEND_VAR OP1[ !1 ] 9 DO_FCALL OP1[ 'pack' ] 10 FETCH_OBJ_W RES[ $4 ] OP1[ UNUSED ] OP2[ '_array' ] 11 ZEND_ASSIGN_DIM OP1[ $4 ] OP2[ UNUSED ] 12 ZEND_OP_DATA RES[ UNUSED ] OP1[ $6 ] OP2[ $7 ] 5 13 JMP OP1[ ->4 ] 14 SWITCH_FREE RES[ UNUSED ] OP1[ $1 ] 6 15 RETURN OP1[ 1 ] 16* ZEND_HANDLE_EXCEPTION

SwiftMailer Examples Implementation 2 $to_add = str_split ( $bytes ); // Convert string to char array /* add the array as first arg of the function */ array_unshift ( $to_add , & $this -> _array ); // Will trigger E_STRICT /* Push all elements in one function call and get the count */ $this -> _arraySize = call_user_func_array ('array_push' , $to_add ); compiled vars: !0 = $to_add, !1 = $bytes line # op return operands -------------------------------------------------------------------------- 2 0 SEND_VAR OP1[ !1 ] 1 DO_FCALL OP1[ 'str_split' ] 2 ASSIGN OP1[ !0 ] OP2[ $0 ] 4 3 SEND_REF RES[ UNUSED ] OP1[ !0 ] OP2[ UNUSED ] 4 FETCH_OBJ_W RES[ $2 ] OP1[ UNUSED ] OP2[ '_array' ] 5 SEND_REF RES[ UNUSED ] OP1[ $2 ] OP2[ UNUSED ] 6 DO_FCALL OP1[ 'array_unshift' ] 6 7 SEND_VAL OP1[ 'array_push' ] 8 SEND_VAR OP1[ !0 ] 9 DO_FCALL OP1[ 'call_user_func_array' ] 10 ZEND_ASSIGN_OBJ OP1[ UNUSED ] OP2[ '_arraySize' ] 11 ZEND_OP_DATA RES[ UNUSED ] OP1[ $5 ] OP2[ UNUSED ] 7 12 RETURN OP1[ 1 ] 13* ZEND_HANDLE_EXCEPTION

SwiftMailer Examples Implementation 3 $to_add = str_split ( $bytes ); // Convert string to char array /* Calls array Merge */ /* Array merge works by copying the first array element By element, then the second, third, … The speed decreases with the number of items in each array */ $this -> _array = array_merge ( $this -> _array , $to_add ); $this -> _arraySize = count ( $this -> _array ); compiled vars: !0 = $to_add, !1 = $bytes line # op return operands ------------------------------------------------------------------------------- 2 0 SEND_VAR OP1[ !1 ] 1 DO_FCALL OP1[ 'str_split' ] 2 ASSIGN OP1[ !0 ] OP2[ $0 ] 7 3 FETCH_OBJ_R RES[ $3 ] OP1[ UNUSED ] OP2[ '_array' ] 4 SEND_VAR OP1[ $3 ] 5 SEND_VAR OP1[ !0 ] 6 DO_FCALL OP1[ 'array_merge' ] 7 ZEND_ASSIGN_OBJ OP1[ UNUSED ] OP2[ '_array' ] 8 ZEND_OP_DATA RES[ UNUSED ] OP1[ $4 ] OP2[ UNUSED ] 8 9 FETCH_OBJ_R RES[ $6 ] OP1[ UNUSED ] OP2[ '_array' ] 10 SEND_VAR OP1[ $6 ] 11 DO_FCALL OP1[ 'count' ] 12 ZEND_ASSIGN_OBJ OP1[ UNUSED ] OP2[ '_arraySize' ] 13 ZEND_OP_DATA RES[ UNUSED ] OP1[ $7 ] OP2[ UNUSED ] 10 14 RETURN OP1[ 1 ] 15* ZEND_HANDLE_EXCEPTION

SwiftMailer Examples Implementation 4 $to_add = str_split ( $bytes ); foreach ( $to_add as $value ) { $this -> _array [] = $value ; } $this -> _arraySize = count ( $this -> _array ); compiled vars: !0 = $to_add, !1 = $bytes, !2 = $value line # op return operands -------------------------------------------------------------------------- 1 0 SEND_VAR OP1[ !1 ] 1 DO_FCALL OP1[ 'str_split' ] 2 ASSIGN OP1[ !0 ] OP2[ $0 ] 2 3 FE_RESET RES[ $2 ] OP1[ !0 ] OP2[ ->11 ] 4 FE_FETCH RES[ $3 ] OP1[ $2 ] OP2[ ->11 ] 5 ZEND_OP_DATA RES[ UNUSED ] OP1[ UNUSED ] OP2[ UNUSED ] 6 ASSIGN OP1[ !2 ] OP2[ $3 ] 3 7 FETCH_OBJ_W RES[ $5 ] OP1[ UNUSED ] OP2[ '_array' ] 8 ZEND_ASSIGN_DIM OP1[ $5 ] OP2[ UNUSED ] 9 ZEND_OP_DATA RES[ UNUSED ] OP1[ !2 ] OP2[ $7 ] 4 10 JMP OP1[ ->4 ] 11 SWITCH_FREE RES[ UNUSED ] OP1[ $2 ] 5 12 FETCH_OBJ_R RES[ $9 ] OP1[ UNUSED ] OP2[ '_array' ] 13 SEND_VAR OP1[ $9 ] 14 DO_FCALL OP1[ 'count' ] 15 ZEND_ASSIGN_OBJ OP1[ UNUSED ] OP2[ '_arraySize' ] 16 ZEND_OP_DATA RES[ UNUSED ] OP1[ $10 ] OP2[ UNUSED ] 6 17 RETURN OP1[ 1 ] 18* ZEND_HANDLE_EXCEPTION

How to optimize?
Be efficient:
Optimize tight loops, one line functions
Highly covered source code (profile your app)
Use tools
Vulcan Logic Dumper (pecl vld)
Xdebug / Zend Debug – Profilers

Other ways
Use built-in functions (except array_* and in_array)
Use Opcode Caching : APC, eAccelerator, XCache, Zend Server, …
Use data Caching : Memcached, …
Optimize your SQL
Access your data by batches
Create PHP Extension
Use other implementations : Facebook's HipHop, phc, Quercus, RoadSend PHP

Questions? Thanks for listening

http://www.symfony-project.org	344
http://www.symfonylab.com	288
http://symfony.com	283
http://swik.net	123
http://www.phphatesme.com	79
http://www.slideshare.net	33
http://pt.minichiello.name	3
http://www.phpframeworks.com	3
http://blog.nxdomain.be	3
http://www.techgig.com	2
http://dev.symfony2developer.com	2
http://translate.googleusercontent.com	2
http://icy:3000	1
http://www.sfexception.com	1
http://webcache.googleusercontent.com	1
http://feeds2.feedburner.com	1
http://www.linkedin.com	1
http://feeds.feedburner.com	1

PHP Performance SfLive 2010

by Xavier De Cock

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