Portable PHP“All for one, one for all.”

Alexandre Dumas

Anatol BelskiPHP SpecialistNovember 2015

Interoperable PHP

Anatol Belski

@weltling

ab@php.net

#php.pecl@efnet

#winphp-dev@freenode

PHP 7.0 release manager

PHP core developer

OSS guy

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OSTC

• PHP

• Hyper-V

• Azure

• Samba

• Docker

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Interoperability

Hardware

Architecture

OS

Program

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A cross-platform program is …

- Hardware

- OS

- Architecture

- …

independent and can run under various constellations.

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Topics

• Filesystem

• Time API

• Performance

• 32- vs 64-bit

• Thread safety

• Beyond

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Brief UNIX/Windows diff

UNIX/Linux

• gcc

• many libs

• processes

• C99

• Ext*, reiserFS, HFS, etc.

• UNIX permissions

Windows

• vc++

• core API + OSS libs

• threads

• C99 starting with VC12

• NTFS, FAT

• ACLs

Filesystem

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File permissions

UNIX/Linux

• chmod +x file

• chmod -r file

• chmod ugo-r file

• chmod +r file

• no equivalent

• no equivalent

• chmod +t somedir

Windows

• no equivalent

• icacls file /deny nick:(R)

• no equivalent

• icacls file /grant nick:(R)

• icacls file /grant nick:(GR,GW)

• icacls file /inheritance:e

• no equivalent

Interoperable PHP

File/process permissions

• UNIX/Linux• chmod(), chown(), etc.

• process permissions are handled same way as file ones

• Windows• icacls

• impersonation

• Unmapped UNIX users built-in SID mapping

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Access time

• ext3, ext4 and others• noatime,nodiratime in /etc/fstab

• NTFS• fsutil behavior query DisableLastAccess

• fsutil behavior set DisebleLastAccess 0

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NTFS streams

C:\tmp> echo hello > foo.txt

C:\tmp>echo world > foo.txt:bar.txt

C:\tmp>dir /r foo.txt

Volume in drive C is SYSTEM

Volume Serial Number is AE0A-76BD

Directory of C:\tmp

08/31/2015 11:50 PM 8 foo.txt

8 foo.txt:bar.txt:$DATA

1 File(s) 8 bytes

0 Dir(s) 59,944,050,688 bytes free

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PHP FS snippet 1

<?php

var_dump(file_exists("/"));

// Windowsbool(true)

//Linuxbool(true)

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PHP FS snippet 2

<?php

var_dump(dirname('/windows/system', 2));

// Windowsstring(1) "\“

//Linuxstring(1) “/"

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PHP FS snippet 3

<?php

$f = fopen("file.txt", "w");

var_dump(unlink("file.txt"));

// Windows

Warning: unlink(file.txt): Permission denied in Command line code on line 1

bool(false)

//Linux

bool(true)

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PHP FS snippet 4

<?php

var_dump(fopen("some/directory", "r"));

// Windows

Warning: fopen(some/directory): failed to open stream: Permission denied in Command line code on line 1

bool(false)

//Linux

resource(5) of type (stream)

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Some PHP FS functions

• readdir()

• glob()

• symlink()

• relapath()

• temp dir

• PHP extension paths

Time APIs

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System time APIs

• TSC• RDTSC

• RDTSCP

• PM clock

• HPET timer

• POSIX clock

• WIN8+

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gettimeofday()

• UNIX/Linux• us resolution + dependency on userspace tools

• Windows• Win8+ with resolution <1us

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Time examples in PHP

• microtime() != microtime()

• uniqid() is based on usleep()

• usleep()

• timeout handling

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Timeout handling

<?php

set_time_limit(3);

/* do some work */

$until = microtime(true) + 2;

while($until > microtime(true));

sleep(1);

/* do some work */

$until = microtime(true) + 1;

while($until > microtime(true));

cho “reached here”;

PHP Performance

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PHP opcode caches

• Opcache

• WinCache

• APC

• APCu

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Performance PHP way

• QB extension

• Zephir

• Recki-ct

• Memcache, etc.

• Write good PHP

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Performance compiler way

• PGO (VC++)

• LTO/FDO (gcc)

• Assembler

• Compiler intrinsics

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PGO

Instrument

• Produce an instrumented build

Train

• Run training scenarios

Optimize

• Produce optimized build using the training data

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PGO commands

• configure –enable-pgi

• nmake

• x64\Release\php.exe run-training-script.php

• nmake clean

• configure –enable-pgo

• nmake

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FDO commands

• make clean

• make prof-gen

• sapi/cli/php run-training-script.php

• make prof-clean

• make prof-use

64-bit

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Do you think this works?

$x = str_repeat("x", PHP_INT_MAX);

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64- vs 32-bit in PHP

64-bit

• In general slower

• 9.22337204 × 109 GB RAM addressable

• 64-bit integers

• LFS

• 64-bit string length

32-bit

• In general faster

• Less than 2 GB RAM addressable

• 32-bit integers

• 32-bit file operations

• 32-bit string length

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Types in PHP7

• zend_long for integers

• zend_ulong for numeric hashes

• size_t for string length

• zend_off_t for file offsets

• zend_stat_t for file status information

• See UPGRADING for more info

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64-bit affecting some functions

• stat()

• lstat()

• filesize()

• substr()

• ftell()

• fseek()

Treads vs. Processes

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Process

Program code

OS

Processor core #n

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Threads

Thread #3

Thread #1

Thread #2

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Process/Thread

Process single threaded

stack

text

data

heap

Process multi threaded

stack

stack

text

data

heap

Thread 1

Thread 2

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Treads vs processes

• Thread locking

• Shared memory

• security

• performance

Thread 1

Thread 2

static __thread int i = 0; static int j = 0; void start_thread(void *dummy) { char hello[6]; char *world; memcpy(hello, "hello", 5); world = malloc(sizeof(char) * 5); memcpy(world, "world", 5); i++; } int main(int argc, char **argv) { pthread_t t0, t1; rc = pthread_create(&t0, NULL, start_thread, NULL); rc = pthread_create(&t1, NULL, start_thread, NULL); return 0; }

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PHP SAPIs

• Apache (worker, prefork, winnt)

• CGI/FastCGI/FPM (NGINX, IIS, Apache, etc.)

• Embed

• Many unsupported SAPIs removed in PHP7

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Apache mpm_prefork

Master

Child 1

Child 2

Child n

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Apache mpm_worker

Master

Child 1

Child 2

Child n

\\\\\\\\\\\v

Thread 1

Thread 2

Thread n

\\\\\\\\\\\v

\\\\\\\\\\\v

Thread 1

Thread 2

Thread n

\\\\\\\\\\\v

\\\\\\\\\\\v

\\\\\\\\\\\v

Thread 1

Thread 2

Thread n

\\\\\\\\\\\v

\\\\\\\\\\\v

\\\\\\\\\\\v

\\\\\\\\\\\v

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Apache mpm_winnt

\\\\\\\\\\\v

Master Child

Thread 1

Thread 2

Thread n

\\\\\\\\\\\v

\\\\\\\\\\\v\\\\\\\\\\\v

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void ***tsrm_ls in PHP 5

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TS layer in PHP 7

• Global thread specific pointer per binary unit

• Optional special setup to cache TS resource

• No additional tsrm_ls arguments in functions

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TLS

● __thread qualifier is not a standard

● __declspec(thread) is not a standard

● thread_local is C++11 standard (not in PHP)

● pthread_setspecific, TlsSetValue, etc.

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TLS types in PHP 7TSRM/TSRM.h

#ifdef TSRM_WIN32# define TSRM_TLS __declspec(thread)#else# define TSRM_TLS __thread#endif

Zend/zend_types.h

#ifdef ZTS#define ZEND_TLS static TSRM_TLS#define ZEND_EXT_TLS TSRM_TLS#else#define ZEND_TLS static#define ZEND_EXT_TLS#endif

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TS or NTS with PHP?

TS

• Less RAM consuming

• Faster startup

• Less library compatibility

• More complexity

• Slower processing

NTS

• More RAM consuming

• Slower startup

• More library compatibility

• Less complexity

• Faster processing

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Some PHP core functions

• mt_rand()

• fork()

• chroot()

• setlocale()/localeconv()

• symlink()/link()

• fputcsv()

• mail()

• getenv()/putenv()

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C APIs implementations in PHP

snprintf sprintf spprintf strlcat strlcpyglob sscanf strnatcmp strtodgettimeofday usleep nanosleepselect opendir readdir rewinddirflock socketpair syslog openlogcloselog ...

Questions?

Thanks for your attention!

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Links

• https://msdn.microsoft.com/en-us/library/e7k32f4k.aspx

• http://blogs.msdn.com/b/vcblog/archive/2013/05/06/speeding-up-php-performance-for-your-application-using-profile-guided-optimization-pgo.aspx

• https://msdn.microsoft.com/en-us/library/windows/desktop/aa364404%28v=vs.85%29.aspx

• https://wiki.php.net/rfc/removal_of_dead_sapis

• https://wiki.php.net/rfc/remove_deprecated_functionality_in_php7

• https://wiki.php.net/rfc/native-tls

• https://wiki.php.net/rfc/size_t_and_int64_next