EAcceleratorCacheFunction = Cache_Lite_Function + EAccelerator

It’s pretty much all in the title. In a nutshell, EAcceleratorCacheFunction is a “memoizing” cache class for PHP that uses shared memory for storage. It is mostly compatible with Cache_Lite and Cache_Lite_Function.

Just like Cache_Lite_Function, it supports per-cache-object lifetime values, instead of specifying the lifetime of an item at the time you store it. This lets you dynamically change the lifetime of the cache. For example, if system load goes up and you don’t mind serving sightly older content instead of regenerating it:

$load = sys_getloadavg();
// use 5 min avg (ignore momentary spikes)
if($load[1] >= 6) {
    $lifetime = 900; # 15 min
} elseif($load[1] >= 3) {
    $lifetime = 600; # 10 min
} else {
    $lifetime = 300; # 5 min
}
$cache = new EAcceleratorCacheFunction(array('lifeTime' => $lifetime));
$cache->call('make_page');

I wrote EAcceleratorCacheFunction as a drop-in replacement for Cache_Lite_Function. On a virtual private server, doing cache reads/writes from memory instead of disk has made a noticeable difference in performance; it helps tremendously that the database has to contend with less disk I/O.