APC + Phar Performance (x-post from pecl.dev)

Hi all,

After re-testing this scenario against Zend Optimizer+ on OS.X in 5.4
yesterday ...

it's worth noting that Zend Optimizer+ does not suffer from the same
file stat/include_path problems that APC does when dealing with phars.

An unpacked phar to filesystem (with autoloader, using absolutely path
with DIR) performs the same as phar (autoloader as stub using
include 'phar://' . FILE . '/' . $fileInPhar).

-ralph

Hey all,

After reading this post (
http://www.reddit.com/r/PHP/comments/13uwgk/phar_performance/ ), and
having my own curiosity of the current state of things, I wanted to dig
in an see what the performance of APC with phar files was.

I've found some oddities in performance, and I am hoping before I do any
deeper investigation, someone might know something.

The app is here:
https://github.com/ralphschindler/test-phar-performance-apc/

The library I am attempting to introduce to the app is Zend_Db.phar. I
chose this b/c I fully know the code base, and the phar clocks in at
519844 bytes uncompressed.

It breaks down like this:
/index.php - baseline app without addition of library
/index-with-filesys.php - Zend_Db library extracted to filesystem
/index-with-phar.php - Zend_Db as phar included

Without APC, on my machine, I get a slight drop off, but acceptable.
With APC, the drop off in performance is very noticable. Even with
stat=0, only in a very specific usage scenario (described below) does it
actually nullify phar vs. filesystem.

Without APC (enabled=0)

$ ab -H "Connection: close" -n 500 http://test.dev/index-with-filesys.php

Requests per second: 111.19 [#/sec] (mean)
Time per request: 8.994 [ms] (mean)

$ ab -H "Connection: close" -n 500 http://test.dev/index-with-phar.php

Requests per second: 87.49 [#/sec] (mean)
Time per request: 11.429 [ms] (mean)

Then APC 3.1.13 (Beta) is introduced, the app is clearly faster on the
filesystem, but not nearly as fast one would expect in the phar version:

With APC (enabled=1, stat=1)

$ ab -H "Connection: close" -n 500 http://test.dev/index-with-filesys.php

Requests per second: 474.47 [#/sec] (mean)
Time per request: 2.108 [ms] (mean)

$ ab -H "Connection: close" -n 500 http://test.dev/index-with-phar.php

Requests per second: 238.84 [#/sec] (mean)
Time per request: 4.187 [ms] (mean)

With APC (enabled=1, stat=0)

$ ab -H "Connection: close" -n 500 http://test.dev/index-with-filesys.php

Requests per second: 529.02 [#/sec] (mean)
Time per request: 1.890 [ms] (mean)

$ ab -H "Connection: close" -n 500 http://test.dev/index-with-phar.php

Requests per second: 246.71 [#/sec] (mean)
Time per request: 4.053 [ms] (mean)

With APC (enabled=1, stat=0) (With include_path hack)

If this line:

require '../vendor/Zend_Db-2.1.0beta1.phar';

is swapped out with this (to ensure the require is relative to include):

set_include_path('.:' . realpath(DIR . '/../vendor'));
require 'Zend_Db-2.1.0beta1.phar';

I get the following:

$ ab -H "Connection: close" -n 500 http://test.dev/index-with-phar.php

Requests per second: 522.68 [#/sec] (mean)
Time per request: 1.913 [ms] (mean)

Can someone help me make sense of all this? Here are my questions:

• The phar files are listed in the apc_cache_info() with >1 hits, are
  the stat's to those phar files really much slower than to filesystem files?

• Why does the include_path trick affect performance with regards to
  phar files?

-ralph