One of the pages in one of my apps runs very slowly on the web server compared to my local test server. There are some radical differences in the environments that might explain it, but I'm hoping for a more solvable solution than that.
Server:
Solaris 10
Apache 2.2.9 Prefork
PHP 5.2.6
The server is run on a cluster of 4 not-even-a-year-old Sun boxes, and shouldn't be having any issues performance-wise.
Local Test Server:
Windows XP
Apache 2.2.14 WinNT
PHP 5.3.1
This is actually my own desktop - a decent machine, but should pale in comparison to the Sun boxes.
The application is written with CodeIgniter, and I've used the profiling features within to trace the slowdown to Model::Model(). For example, Model::Model() runs in 0.0006s locally and 0.0045s on the server. When you're loading hundreds of models on a page, this is obviously an issue.
I've cross-posted this here from ServerFault, as it could, potentially, be more closely related to CodeIgniter.
From local, the page takes 2-3 seconds to load. From the server, it's 11-15.
Modules on Local, but not remote:
- mod_actions
- mod_asis
- mod_dav mod_dav_fs
- mod_dav_lock
- mod_isapi mod_autoindex_color
Modules on remote, not Local:
- mod_authn_dbm
- mod_authn_anon
- mod_authz_dbm
- mod_authz_owner
- mod_cache
- mod_mem_cache
- mod_deflate
- mod_authnz_ldap
- mod_ldap
- mod_mime_magic
- mod_expires
- mod_unique_id
- mod_autoindex
- mod_suexec
- mod_userdir
- libphp5
- mod_dtrace
- mod_security2
Edit:
I've been moving my benchmarking progressively down, level by level, and have found the largest discrepancy lies within this chunk of code (which is in the CodeIgniter function Model::_assign_libraries, and is called during a model's constructor):
$time = microtime()*1000;
foreach (array_keys(get_object_vars($CI)) as $key)
{
if ( ! isset($this->$key) AND $key != $this->_parent_name)
{
// In some cases using references can cause
// problems so we'll conditionally use them
if ($use_reference == TRUE)
{
$this->$key = NULL; // Needed to prevent reference errors with some configurations
$this->$key =& $CI->$key;
}
else
{
$this->$key = $CI->$key;
}
}
}
if (get_class($this) == 'SeatType')
echo sprintf('%.5f ms|', (microtime()*1000 - $time));
Locally, this prints around 0.48ms every iteration. On the cluster, it prints around 3.9ms every iteration.
I'm beginning to wonder if this problem is outside of Apache/PHP - I copied both the php.ini and htconf files to my local server, and (after removing mod_dtrace, and pretty much nothing else), I actually saw increased performance. (The above check now prints .2ms locally.)