open/close calls of include_once/require_once files.

A couple of notes.

You make it sound like this happens on all includes. It is only
include_once/require_once that have this problem. Regular
include/require do not.

This has been addressed in APC by overriding the opcode and providing
our own opcode handler for this case. See
http://svn.php.net/viewvc/pecl/apc/trunk/apc_zend.c?view=markup&pathrev=289331
line 86.

Having said that, it would be preferable, of course, if we didn't need
to swap out that code in APC but I am not sure your solution for solving
this only for absolute path includes is the right way to go here.

-Rasmus

Basant Kukreja wrote:

Hi,
When php script includes a script, php engine compiles the included file.
When opcode caching extensions e.g apc are used, re-compilation is avoided by
apc. But there is a performance problem here. Since php code uses
zend_stream_open to open the included file, open/close system call is still
there. When used with APC, open/close doesn't do any good for file-system based
files. It only provides the realpath of the opened file. In php 5.3,
zend_resolve_path already provides the realpath of the file being opened so we
can avoid an open/close calls for file to be included if file is an absolute
path.

Current php 5.3 implementation for include_once/require_once (pseudo code)

a) call zend_resolve_path. It will provide the realpath. Symlinks are taken
care of by zend_resolve_path.
b) Check if file is already included. If yes, do nothing else go to step (c)
c) Call zend_stream_open and get the included_file realpath.
d) Invoke zend_compile_file and do the rest.

Now zend_stream_open invokes the open/close calls to the including files which
is redundant when caches are used.

Here is the suggested performance fix :
a) Same as previous
b) Same as previous
c) If resolved_path is an absolute path then do step c.1 else do c.2
c.1) Prepare a file_handle and directly invoke zend_compile_file
c.2 Call zend_stream_open and get the included_file realpath.
b) Same as previous

---

Few notes :

• Performance improvements using this patch = ~1.5% in an e-commerce workload.
• Testing : I ran the php 5.3 test suite and didn't find any regression.
• If files which are included are not absolute paths then they will follow
  the same zend_stream_path route.
• Tested with symlinks and found the behaviour is expected (no change).

I have attached the patch for review comments.

Regards,
Basant.

Note: I previously did this work for php 5.2 but bug remains still open. 5.3
implementation is relatively straight forward. Here is the reference to 5.2 bug
: http://bugs.php.net/bug.php?id=47660&thanks=2