php-ffi-rdtsc

Expose the __rdtsc CPU cycle counter to user-land using a php extension

Requirements

• x64 platform
• gcc

Usage

phpize
./configure
make
php -d extension=modules/rdtsc.so example.php

Notes

Given the various caveats with __rdtsc this should be used with great care when trying to measure things.

There also is a PHP-FFI implementation that provides the same functionality available.

For most cases getrusage() should be preferable.

References

• Wikipedia - Time Stamp Counter
• Microsoft cpp intrinsics __rdtsc
• Intel - How to Benchmark Code Execution Times on Intel® IA-32 and IA-64 Instruction Set Architectures
• Online x64 reference