JIT: So what?

Transcript

1. Ricardo Coelho – @ramcoelho
   JIT
   So what?
   

   View Slide

2. View Slide

3. JIT
   So what?
   

   View Slide

4. 5 ➞ 7
   

   View Slide

5. opcache
   

   View Slide

6. opcache
   CPU
   

   View Slide

7. opcache
   ARM
   MIPS
   X86
   

   View Slide

8. Optimizations
   Escape Analysis
   

   View Slide

9. $newVariable = ‘undefined’;
   if ($isTrue) {
   $newVarible = ‘true’;
   } else {
   $newVariable = ‘false’;
   }
   Optimizations (DCE)
   $newVariable = ‘false’;
   if ($isTrue) {
   $newVarible = ‘true’;
   }
   

   View Slide

10. function f($x) {
    $a = 15;
    $b = 5 * $a;
    return $x;
    }
    echo f(“test”);
    Optimizations
    echo “test”;
    

    View Slide

11. 5 ➞ 7
    

    View Slide

12. 200% Drupal
    300% Magento
    400% Wordpress
    5 ➞ 7
    source: www.zend.com/blog/php-7
    

    View Slide

13. 01 02
    03 ;
    

    View Slide

14. So, you’re telling me
    that after upgrading to
    PHP 7 your code is
    running a lot faster?
    Congratulations,
    your code sucks!
    

    View Slide

15. 7 ➞ 8
    

    View Slide

16. JIT
    

    View Slide

17. ust n ime
    J I T
    

    View Slide

18. https://youtu.be/dWH65pmnsrI
    

    View Slide

19. 01 02
    03 echo “Hello World!”;
    0000000 cf fa ed fe 07 00 00 01 03 00 00 00 02 00 00 00
    0000010 10 00 00 00 58 05 00 00 85 00 20 00 00 00 00 00
    0000020 19 00 00 00 48 00 00 00 5f 5f 50 41 47 45 5a 45
    0000030 52 4f 00 00 00 00 00 00 00 00 00 00 00 00 00 00
    (…)
    000c0f0 5f 73 74 75 62 5f 62 69 6e 64 65 72 00 5f 5f 64
    000c100 79 6c 64 5f 70 72 69 76 61 74 65 00 00 00 00 00
    

    View Slide

20. Interpreted
    vs.
    Compiled
    

    View Slide

21. Monitor / Profiler
    

    View Slide

22. Warm code
    

    View Slide

23. Hot code optimization
    

    View Slide

24. opcache
    ARM
    MIPS
    X86
    

    View Slide

25. opcache
    ARM
    MIPS
    X86
    jit
    

    View Slide

26. docker run --rm php:8.0.0-cli php -v
    Let’s test it…
    

    View Slide

27. docker run --rm -it php:8.0.0-cli bash
    Let’s test it…
    

    View Slide

28. @host$ docker run --rm -it php:8.0.0-cli bash
    @php8$ echo “@php8$ docker-php-ext-enable opcache
    @php8$ echo “Let’s test it…
    

    View Slide

29. @host$ wget https://bit.ly/jit-so-what
    @host$ unzip jit-so-what
    @host$ cd jit-so-what—1.0
    @host$ docker run --rm -it -p 80:80
    -v $(pwd)/php.ini:/usr/local/etc/php/php.ini
    -v $(pwd):/app
    php:8.0.0-cli bash
    Let’s test it…
    

    View Slide

30. @php8$ php /app/run.php
    @php8$ php -S 0.0.0.0:80 -t /app
    @host$ ab -n 40 -c 20 -l http://localhost/run.php
    @php8$ docker-php-ext-enable opcache
    @host$ ab -n 40 -c 20 -l http://localhost/run.php
    Let’s test it…
    

    View Slide

31. Results
    Concurrency Level: 20
    Time taken for tests: 77.639 seconds
    Complete requests: 40
    Failed requests: 0
    Total transferred: 252800 bytes
    HTML transferred: 246520 bytes
    Requests per second: 0.52 [#/sec] (mean)
    Time per request: 38819.662 [ms]
    (mean)
    Time per request: 1940.983 [ms]
    (mean, across all concurrent requests)
    Transfer rate: 3.18 [Kbytes/sec]
    received
    Concurrency Level: 20
    Time taken for tests: 7.673 seconds
    Complete requests: 40
    Failed requests: 0
    Total transferred: 252800 bytes
    HTML transferred: 246520 bytes
    Requests per second: 5.21 [#/sec] (mean)
    Time per request: 3836.614 [ms]
    (mean)
    Time per request: 191.831 [ms]
    (mean, across all concurrent requests)
    Transfer rate: 32.17 [Kbytes/sec]
    received
    JIT
    ❤
    

    View Slide

32. source: www.php.net/releases/8.0/en.php
    

    View Slide

33. Types, DOM and
    frustrated expectations
    (failed guard)
    

    View Slide

34. Deoptimization
    (bailout)
    

    View Slide

35. I/O bound?
    Little to no reuse?
    Short lifespan execution?
    ➞ i.e. Web Applications
    

    View Slide

36. 5-20 %
    

    View Slide

37. Is it worth the trouble?
    

    View Slide

38. • extension developers who would prefer to write it in PHP,
    instead of C;
    
    • CPU intensive code;
    
    • strongly typed variables and well-defined and stable data
    structures;
    
    • squeezing the last drop of performance.
    It is worth for…
    

    View Slide

39. Questions?
    Thank You!
    

    View Slide

40. • https://wiki.php.net/rfc/jit
    
    • https://stitcher.io/blog/new-in-php-8
    
    • https://stitcher.io/blog/php-jit
    
    • https://stitcher.io/blog/jit-in-real-life-web-applications
    
    • https://kinsta.com/pt/blog/php-8/
    
    • https://hacks.mozilla.org/2017/02/a-crash-course-in-just-in-time-jit-compilers/
    
    • https://github.com/mente/php-docker-jit
    
    • https://mobile.twitter.com/dr4goonis/status/806817526097346560

    References
    

    View Slide