Tideways XHProf Extension

Home of the tideways_xhprof extension.

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This PHP extension is a complete, modernized open-source rewrite of the original XHProf extension, with a new core datastructure and specifically optimized for PHP 7. The result is an XHProf data-format compatible extension with a much reduced overhead in the critical path that you are profiling.

The code for this extension is extracted from the main Tideways extension as we are moving to a new extension with incompatible data-format.

We are committed to provide support for this extension and port it to as many platforms as possible.

Note: The public API is not compatible to previous xhprof extensions and forks, as function names are different. Only the data format is compatible.

About tideways and tideways_xhprof Extensions

This repository now contains an extension by the name of tideways_xhprof, which only contains the XHProf related (Callgraph) Profiler functionality.

Previously the tideways extension contained this functionality together with other functionality used in our Software as a Service.

If you want to use the SaaS you must fetch the code using precompiled binaries and packages from our Downloads page.

We don't provide new open-source releases of our own Profiler anymore.

Requirements

• PHP >= 7.0
• OS: Linux only (at the moment)

Installation

You can install the extension from source:

phpize
./configure
make
sudo make install

Configure the extension to load with this PHP INI directive:

extension=tideways_xhprof.so

Restart Apache or PHP-FPM.

Usage

The API is not compatible to previous xhprof extensions and forks, only the data format is compatible:

<?php

tideways_xhprof_enable();

my_application();

$data = tideways_xhprof_disable();

file_put_contents("/tmp/profile.xhprof", serialize($data));

By default only wall clock time is measured, you can enable there additional metrics passing the $flags bitmask to tideways_xhprof_enable:

<?php

tideways_xhprof_enable(TIDEWAYS_XHPROF_FLAGS_MEMORY | TIDEWAYS_XHPROF_FLAGS_CPU);

my_application();

$data = tideways_xhprof_disable();

Data-Format

The XHProf data format records performance data for each parent => child function call that was made between the calls to tideways_xhprof_enable and tideways_xhprof_disable. It is formatted as an array with the parent and child function names as a key concatenated with ==> and an array value with 2 to 5 entries:

• wt The summary wall time of all calls of this parent ==> child function pair.
• ct The number of calls between this parent ==> child function pair.
• cpu The cpu cycle time of all calls of thi sparent ==> child function pair.
• mu The sum of increase in memory_get_usage for this parent ==> child function pair.
• pmu The sum of increase in memory_get_peak_usage for this parent ==> child function pair.

There is a "magic" function call called "main()" that represents the entry into the profiling. The wall time on this performance data describes the full timeframe that the profiling ran.

Example:

<?php

array(
    "main()" => array(
        "wt" => 1000,
        "ct" => 1,
        "cpu" => 900,
    ),
    "main()==>foo" => array(
        "wt" => 500,
        "ct" => 2,
        "cpu" => 200,
    ),
    "foo==>bar" => array(
        "wt" => 200,
        "ct" => 10,
        "cpu" => 100,
    ),
)