Boost PHP 7 Performance: Essential Tweaks and Opcache Tips

PHP 7.0.0 Release

PHP development team announced PHP 7.0.0 is now available, marking the start of the PHP 7 series.

Key Improvements

Performance up to twice that of PHP 5.6

Significant memory usage reduction

Abstract Syntax Tree

Full 64‑bit support

Improved exception hierarchy

Many fatal error conversions

Secure random number generator

Removal of old and unsupported SAPIs and extensions

Null coalescing operator (??)

Return and scalar type declarations

Anonymous classes

Zero‑cost abstractions

Performance Tuning Tips

To get the most out of PHP 7, consider the following:

1. Enable Opcache

Add the following to php.ini:

zend_extension=opcache.so
opcache.enable=1
opcache.enable_cli=1

2. Use a newer compiler

Compile with GCC 4.8 or newer to enable Global Register for opline and execute_data, yielding about 5% performance gain for WordPress workloads.

3. Enable HugePages

Activate HugePages in the OS and set opcache.huge_code_pages=1 in php.ini. Example for CentOS 6.5:

sudo sysctl vm.nr_hugepages=512
cat /proc/meminfo | grep Huge

4. Opcache file cache

Enable experimental file cache to store opcodes on disk:

opcache.file_cache=/tmp

5. Profile‑Guided Optimization (PGO)

Build PHP with PGO for a specific project (e.g., WordPress). Example steps:

make prof-gen
sapi/cgi/php-cgi -T 100 /path/to/wordpress/index.php >/dev/null
make prof-clean
make prof-use

The resulting binary is tailored for maximum performance for that workload.