The apache configuration file (usually httpd.conf) that ships with most linux distros has some configuration settings that are sub-optimal for running PHP applications (many optimizations described below will benefit other applications as well). I've found, after a bit of trial and error, that the following settings will let you squeeze a little extra out of the server running on your development machine.
The settings below affect the overall memory usage (even when idle) of the server since they define the minimum number of httpd processes (or threads) that are spawned and maintained. On my laptop, with 4GB RAM, the prefork and mpm worker settings are as follows (apache only uses one of them, depending on how it is compiled):
<IfModule prefork.c> StartServers 8 MinSpareServers 5 MaxSpareServers 20 ServerLimit 50 MaxClients 50 MaxRequestsPerChild 300 #Respawn a process after serving 300 requests. Curtails footprint bloat due to memory leaks. </IfModule> <IfModule worker.c> StartServers 2 MaxClients 50 MinSpareThreads 25 MaxSpareThreads 50 ThreadsPerChild 25 MaxRequestsPerChild 300 </IfModule>
Other than tweaking the process/thread variables, there are a few more settings to look at:
KeepAlive On #Reduces page load time by reusing tcp connections MaxKeepAliveRequests 100 KeepAliveTimeout 15 #Set this value higher for longer-lived connections between browser and server, but if there are many simultaneous requests, this can cause some of them to unnecessarily queue up. FileETag None
Additionally, you can instruct apache to compress content sent over the network using gzip by adding the following lines (I've put them in a separate mod_deflate.conf under /etc/httpd/conf.d, but that's not necessary):
#GZIP configuration for enabling compresion SetOutputFilter DEFLATE BrowserMatch ^Mozilla/4 gzip-only-text/html BrowserMatch ^Mozilla/4\.0 no-gzip BrowserMatch \bMSI[E] !no-gzip !gzip-only-text/html SetEnvIfNoCase Request_URI \ \.(?:gif|jpe?g|png)$ no-gzip dont-vary Header append Vary User-Agent env=!dont-vary
Assuming you're doing PHP development, you might as well go ahead and enable APC. I've sometimes faced an issue with APC using stale opcode even when a newer version of the source file is available, but not very often. Some people prefer to keep APC disabled on development machines. In /etc/php.d/apc.ini (on Red Hat-like systems, including Fedora, CentOS, RHEL, Amazon Linux, etc.) enable the following settings:
apc.enabled=1 apc.shm_size=512M ; This is usually too much if you're running just one application. ; It's better to start with 128 MB and upscale only if this falls short. ; You can check APC memory usage using the apc.php file that ships with the default APC installation on most systems. ; (http://pecl.php.net/package/APC)
While we're on the subject of optimization, we might as well tune our MySQL server to use its built-in query cache. In your /etc/my.cnf add the following line:
Restart your apache and mysql servers to apply the new settings.