This document discusses making PHP more interoperable across platforms. It covers differences between UNIX/Linux and Windows filesystem permissions and access times. It also discusses PHP performance optimizations like opcode caching, compiler optimizations, and differences between 32-bit and 64-bit PHP. Additionally, it covers threading versus processes in PHP and differences in SAPIs like Apache. The document provides code examples to illustrate concepts.

1. Portable PHP
“All for one, one for all.”
Alexandre Dumas
Anatol Belski
PHP Specialist
November 2015

2. Interoperable PHP
Anatol Belski
@weltling
ab@php.net
#php.pecl@efnet
#winphp-dev@freenode
PHP 7.0 release manager
PHP core developer
OSS guy

3. Interoperable PHP
OSTC
• PHP
• Hyper-V
• Azure
• Samba
• Docker

5. Interoperable PHP
Interoperability
Hardware
Architecture
OS
Program

6. Interoperable PHP
A cross-platform program is …
- Hardware
- OS
- Architecture
- …
independent and can run under various
constellations.

7. Interoperable PHP
Topics
• Filesystem
• Time API
• Performance
• 32- vs 64-bit
• Thread safety
• Beyond

8. Interoperable PHP
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

9. Filesystem

10. Interoperable PHP
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

11. 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

12. Interoperable PHP
Access time
• ext3, ext4 and others
• noatime,nodiratime in /etc/fstab
• NTFS
• fsutil behavior query DisableLastAccess
• fsutil behavior set DisebleLastAccess 0

13. Interoperable PHP
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

14. Interoperable PHP
PHP FS snippet 1
<?php
var_dump(file_exists("/"));
// Windows
bool(true)
//Linux
bool(true)

15. Interoperable PHP
PHP FS snippet 2
<?php
var_dump(dirname('/windows/system', 2));
// Windows
string(1) "“
//Linux
string(1) “/"

16. Interoperable PHP
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)

17. Interoperable PHP
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)

18. Interoperable PHP
Some PHP FS functions
• readdir()
• glob()
• symlink()
• relapath()
• temp dir
• PHP extension paths

19. Time APIs

20. Interoperable PHP
System time APIs
• TSC
• RDTSC
• RDTSCP
• PM clock
• HPET timer
• POSIX clock
• WIN8+

21. Interoperable PHP
gettimeofday()
• UNIX/Linux
• us resolution + dependency on userspace tools
• Windows
• Win8+ with resolution <1us

22. Interoperable PHP
Time examples in PHP
• microtime() != microtime()
• uniqid() is based on usleep()
• usleep()
• timeout handling

23. Interoperable PHP
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”;

24. PHP Performance

25. Interoperable PHP
PHP opcode caches
• Opcache
• WinCache
• APC
• APCu

26. Interoperable PHP
Performance PHP way
• QB extension
• Zephir
• Recki-ct
• Memcache, etc.
• Write good PHP 

27. Interoperable PHP
Performance compiler way
• PGO (VC++)
• LTO/FDO (gcc)
• Assembler
• Compiler intrinsics

28. Interoperable PHP
PGO
Instrument
• Produce an instrumented build
Train
• Run training scenarios
Optimize
• Produce optimized build using the training data

29. Interoperable PHP
PGO commands
• configure –enable-pgi
• nmake
• x64Releasephp.exe run-training-script.php
• nmake clean
• configure –enable-pgo
• nmake

30. Interoperable PHP
FDO commands
• make clean
• make prof-gen
• sapi/cli/php run-training-script.php
• make prof-clean
• make prof-use

31. 64-bit

32. Interoperable PHP
Do you think this works?
$x = str_repeat("x", PHP_INT_MAX);

33. Interoperable PHP
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

34. Interoperable PHP
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

35. Interoperable PHP
64-bit affecting some functions
• stat()
• lstat()
• filesize()
• substr()
• ftell()
• fseek()

36. Treads vs. Processes

37. Interoperable PHP
Process
Program
code
OS
Processor
core #n

38. Interoperable PHP
Threads
Thread #3
Thread
#1
Thread
#2

39. Interoperable PHP
Process/Thread
Process single
threaded
stack
text
data
heap
Process multi
threaded
stack
stack
text
data
heap
Thread 1
Thread 2

40. Interoperable PHP
Treads vs processes
• Thread locking
• Shared memory
• security
• performance

41. 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;
}

42. Interoperable PHP
PHP SAPIs
• Apache (worker, prefork, winnt)
• CGI/FastCGI/FPM (NGINX, IIS, Apache, etc.)
• Embed
• Many unsupported SAPIs removed in PHP7

43. Interoperable PHP
Apache mpm_prefork
Master
Child 1
Child 2
Child n

44. Interoperable PHP
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

45. Interoperable PHP
Apache mpm_winnt
v
Master Child
Thread 1
Thread 2
Thread n
v
vv

46. Interoperable PHP
void ***tsrm_ls in PHP 5

47. Interoperable PHP
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

48. Interoperable PHP
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.

49. Interoperable PHP
TLS types in PHP 7
TSRM/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

50. Interoperable PHP
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

51. Interoperable PHP
Some PHP core functions
• mt_rand()
• fork()
• chroot()
• setlocale()/localeconv()
• symlink()/link()
• fputcsv()
• mail()
• getenv()/putenv()

52. Interoperable PHP
C APIs implementations in PHP
snprintf sprintf spprintf strlcat strlcpy
glob sscanf strnatcmp strtod
gettimeofday usleep nanosleep
select opendir readdir rewinddir
flock socketpair syslog openlog
closelog ...

53. Questions?

54. Thanks for your
attention!

55. Interoperable PHP
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