The PHP (Hypertext preprocessor, a recursive backronym), which is designed as a server-side scripting language is an extremely popular language. It has been deployed in numerous Content Management Systems (CMS) including WordPress. Magento, Drupal, Joomla, etc., that facilitate one to easily create and handle their online presence.
The PHP programming language features an extensively dynamic and interpreted behavior that makes it stand ahead of the crowd. However, there are certain areas that can help further enhance its performance and this includes the absolute use of an Opcode Cache extension.
What is an Opcode Cache Extension?
Whenever a request is received for some PHP code content, the Zend Engine compiles the PHP source code into bytecode that can be used while responding to the request. This process is repeated every time whenever a request is generated, thus the same chunk of code is interpreted and compiled repeatedly with each request; hence, it adds to the request execution time.
The Opcode cache, which is also known as PHP Accelerator, is primarily a module that takes the output of the Zend Engine as an input and then caches the same into the memory.
To save the time, an Opcode cache can be used during the interpretation and compilation process, it simply helps reuse the once compiled result by caching it into the RAM. Therefore now, the Opcode cache is checked first for the cached executable bytecode whenever a request for some PHP content is generated. If it’s found, the bytecode is instantly returned. However, if it’s not found, the Zend Engine will perform its task and compile the code into bytecode, which is then before returning is cached by the Opcode and saved for the future purpose.
Hence, keeping the Opcode enabled is a good practice and is recommended for heavy production sites. Interestingly, it will help deliver improved performance with PHP applications including Drupal, WordPress, etc., the enabled Opcode can drive the performance three times its usual performance. To evaluate the performance gains, you may tune the cache configuration for expansively busy websites.
How can you tune the PHP Opcode cache?
By tuning the cache configuration, you will be able to recognize the performance gains and check whether the Opcode cache is working properly or not. Thus, it is quite imperative to tune the PHP Opcode cache with utmost precision.
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The cache tuning depends on how much you can input, here we are considering the implementation of the XCache for the tuning purpose.
XCache Open-Source Cache:
XCache is ideal for accelerating the PHP performance on servers. It is basically an open-source cache for the opcode. And, for delivering an optimized performance, the XCache optimizes several aspects of the PHP scripts in order to minimize the server load. Most importantly, to reduce the page loading time, it caches the PHP scripts in the compiled form into the RAM (shm) and then, whenever needed it uses the compiled PHP script. By doing so, it makes the page loading process five times faster.
There are e, which offers an insight into the cache and facilitates the tuning process. You can use it to ensure that the installed cache setup is processing properly by simply observing the stats after logging into the page that provides the cache web stats.
While observing the stats in the XCache, one thing that has to be noticed is the value under the column marked as OOMs (Out of Memory). This helps determine the number of non-cached requests that are left due to insufficient memory. The default space assigned to the cache for storage purpose is 64MB of RAM. For those who are hosting a bunch of websites, there wouldn’t be any benefit of the Opcode cache as the number of OOMs for them will incline exponentially and the provided storage will be consumed instantly.
We have to make sure that anything that has the scope of being cached isn’t left un-cached. For the same, you can increase the cache storage size until you get a zero value under the OOMs column. However, a consistently high number of available Opcode cache storage epitomizes that the allocated RAM space is quite large for it, thus you can minimize its memory and save it for executing other processes efficiently.
You can easily tune the cache for your PHP applications using the XCache and enhance their performance to a great extent. Simply follow the above-mentioned guidelines and accomplish our task with great precision for optimized results.