Enable Just-In-Time(JIT) compilation is very important for PHP performance. So I will enable it on PHP 8.2.6. I have a post discussing it with PHP 8.0 in 2021. Now It is 2023, on PHP 8.2.x. It is different.
Last post when I did the performance tests on PHP 8.2.6, the JIT is not enabled.
- The Bench test result is 0.168
- The Micro-bench test result is 1.094
- The Bubble test result is 0.040456056594849
Test Result on PHP8.2.6 with JIT enabled.
When I enabled the JIT on PHP 8.2.6 on the same machine. The test result is below.
The Bench Test Result
simple 0.001 simplecall 0.000 simpleucall 0.000 simpleudcall 0.000 mandel 0.005 mandel2 0.006 ackermann(7) 0.005 ary(50000) 0.002 ary2(50000) 0.001 ary3(2000) 0.005 fibo(30) 0.013 hash1(50000) 0.004 hash2(500) 0.003 heapsort(20000) 0.005 matrix(20) 0.003 nestedloop(12) 0.003 sieve(30) 0.002 strcat(200000) 0.002 ------------------------ Total 0.061
The Micro-Bench Test Result
empty_loop 0.001 func() 0.001 0.000 undef_func() 0.001 0.000 int_func() 0.001 0.000 $x = self::$x 0.059 0.057 self::$x = 0 0.053 0.051 isset(self::$x) 0.047 0.046 empty(self::$x) 0.051 0.049 $x = Foo::$x 0.027 0.025 Foo::$x = 0 0.018 0.016 isset(Foo::$x) 0.020 0.018 empty(Foo::$x) 0.022 0.021 self::f() 0.001 0.000 Foo::f() 0.001 0.000 $x = $this->x 0.008 0.006 $this->x = 0 0.011 0.009 $this->x += 2 0.007 0.005 ++$this->x 0.006 0.005 --$this->x 0.006 0.005 $this->x++ 0.006 0.005 $this->x-- 0.006 0.005 isset($this->x) 0.028 0.026 empty($this->x) 0.030 0.028 $this->f() 0.019 0.018 $x = Foo::TEST 0.029 0.027 new Foo() 0.106 0.105 $x = TEST 0.007 0.005 $x = $_GET 0.031 0.030 $x = $GLOBALS['v'] 0.027 0.026 $x = $hash['v'] 0.001 0.000 $x = $str[0] 0.001 0.000 $x = $a ?: null 0.001 0.000 $x = $f ?: tmp 0.001 0.000 $x = $f ? $f : $a 0.001 0.000 $x = $f ? $f : tmp 0.001 0.000 ------------------------ Total 0.640
The Bubble Test Result
0.022209882736206
Performance comparison
Compared them with the performance without JIT enabled. It is about 63% improvement on the Bench test script, about 41% improvement on the Micro-Bench test script, and about 45% improvement on the Bubble test script.
On average, about 50% performance improvement with JIT enabled.
How to enable JIT on PHP 8.2.6, Ubuntu 22.04LTS.
- SSH to the server, edit the file /etc/php/8.2/mods-available/opcache.ini
- find the place to add following into the file and save it.
// /etc/php/8.2/mods-available/opcache.ini
…
opcache.jit=1255
opcache.jit_buffer_size=100M
Then restart the php8.2-fpm service with the command sudo service php8.2-fpm restart
Check the phpinfo() again.
OK, now the JIT is enabled and working.
Another thing I want to talk about.
Let me discuss a little bit about the values of the opcache.jit.
- opcache.jit = 1205 – all code is JIT compiled
- opcache.jit = 1235 – only selected code portions (based on their relative use) are passed to the JIT compilation
- opcache.jit = 1255 – application code is tracked for compilation by JIT and selected parts of the code are transferred to the compiler
Here is a blog post from droptica.com which is discuss more details about PHP 8 with the JIT compiler.
I am just wondering why the default value of this JIT configuration is disabled. Is it always good to enable it for better PHP script performance?
