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XHProf is a PHP profiler originally written by Facebook, to provide a more lightweight alternative to XDebug. After installing the xhprof PHP module, profiling can be enabled / disabled from PHP code: xhprof_enable(); doSlowOperation(); $profile_data = xhprof_disable(); The returned array wil...

PHP's runtime memory limit is set through the INI directive memory_limit. This setting prevents any single execution of PHP from using up too much memory, exhausting it for other scripts and system software. The memory limit defaults to 128M and can be changed in the php.ini file or at runtime. I...

An extension to PHP called Xdebug is available to assist in profiling PHP applications, as well as runtime debugging. When running the profiler, the output is written to a file in a binary format called "cachegrind". Applications are available on each platform to analyze these files. To...