Implementing PHP Extensions with Zephir, CGO, and JIT: A Performance Comparison

The article introduces multiple approaches for developing PHP extensions: native C extensions generated by ext_skel.php , Zephir, php-cpp, php-x, and CGO. It emphasizes two main implementation modes: wrapping the Zend API directly and using CGO to embed C and Go code.

Zephir example :

<code>//Main 类
final class Zimuge {
  public static function calcFibonacci(int i) {
      if (i < 2) {
          return i;
      }
      return self::calcFibonacci(i - 1) + self::calcFibonacci(i - 2);
  }
}
</code>

Compilation command for Zephir:

<code>zephir build</code>

CGO example (Go code generating a PHP extension):

<code>package main
/*
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
#include "php.h"
#include "php_ini.h"
#include "ext/standard/info.h"
static int le_go2php;
PHP_MINIT_FUNCTION(go2php) { return SUCCESS; }
PHP_MSHUTDOWN_FUNCTION(go2php) { return SUCCESS; }
PHP_RINIT_FUNCTION(go2php) { return SUCCESS; }
PHP_RSHUTDOWN_FUNCTION(go2php) { return SUCCESS; }
PHP_MINFO_FUNCTION(go2php) {
    php_info_print_table_start();
    php_info_print_table_header(2, "go2php support", "enabled");
    php_info_print_table_end();
}
PHP_FUNCTION(go2php_print) {
    zend_long a,b;
    ZEND_PARSE_PARAMETERS_START(1, 1)
        Z_PARAM_LONG(a)
    ZEND_PARSE_PARAMETERS_END();
    b = calcFib(a);
    RETURN_LONG(b);
}
ZEND_BEGIN_ARG_INFO(null, 0)
ZEND_END_ARG_INFO()
const zend_function_entry go2php_functions[] = {
    PHP_FE(go2php_print, null)
    PHP_FE_END
};
zend_module_entry go2php_module_entry = {
    STANDARD_MODULE_HEADER,
    "go2php",
    go2php_functions,
    PHP_MINIT(go2php),
    PHP_MSHUTDOWN(go2php),
    PHP_RINIT(go2php),
    PHP_RSHUTDOWN(go2php),
    PHP_MINFO(go2php),
    "0.1.0",
    STANDARD_MODULE_PROPERTIES
};
#ifdef COMPILE_DL_GO2PHP
ZEND_GET_MODULE(go2php)
#endif
*/
import "C"
func main() {}
</code>

Go implementation of the Fibonacci function used by the extension:

<code>package main
import "C"
//export calcFib
func calcFib(i int) int {
    if i < 2 {
        return i
    }
    return calcFib(i-1) + calcFib(i-2)
}
</code>

Compilation and linking flags for CGO:

<code>CGO_CFLAGS="-g -I`/root/download/php8/bin/php-config --include-dir` -I`/root/download/php8/bin/php-config --include-dir`/main -I`/root/download/php8/bin/php-config --include-dir`/TSRM -I`/root/download/php8/bin/php-config --include-dir`/Zend -I`/root/download/php8/bin/php-config --include-dir`/ext -I`/root/download/php8/bin/php-config --include-dir`/ext/date/lib -DHAVE_CONFIG_H"
CGO_LDFLAGS="-Wl,--export-dynamic -Wl,--unresolved-symbols=ignore-all"
go build -p 1 -gcflags "-l" -buildmode=c-shared -o go2php.so
</code>

A PHP test script runs the Fibonacci calculation using the native PHP function, the Zephir‑generated class, and the CGO‑built extension, measuring execution time with microtime(true) . Results without JIT show CGO fastest (≈0.06 s), Zephir slower (≈8.57 s), and pure PHP slowest (≈0.76 s). With PHP JIT enabled, CGO improves slightly (≈0.047 s), Zephir becomes faster (≈5.59 s), and PHP JIT runs in ≈0.11 s.

The conclusions are:

PHP JIT can noticeably improve performance.

CGO allows Go developers to write PHP extensions without abandoning PHP.

Zephir, while not the fastest, offers a relatively simple way to create PHP extensions.

Additional notes cover loading the compiled .so files via php.ini and verifying them with php -m or php --ri . The PHP version used for testing is 8.1.3.