Adding option to track php functions time with adding actions in the …

[ivdimova]

…code that will be profilled
For #282

[johnbillion]

Yep this is exactly the sort of thing I was thinking, thanks. A few points:

• The QM_Timer class can be used in place of manually calling microtime(). It supports starting, lapping, and stopping a timer and includes the time and memory usage. You can see this in use in the self-awareness output in the develop branch.
• Probably will need to handle timers that were started but not stopped, with a useful warning message.
• We'll need to consider overlapping timers. The start and stop properties in the collector might need to be converted to associative arrays keyed by the function name. Example that needs to be handled:

do_action( 'qm/start', 'function_1' );
do_action( 'qm/start', 'function_2' );
...
do_action( 'qm/stop', 'function_1' );
do_action( 'qm/stop', 'function_2' );

[eddr]

Will you have to manually add "do_action" for each function you want to measure? if so, that's fine, but what about functions inside classes or if you want to get a measurement of the whole system at once?

[crstauf]

@eddr Interesting idea: a single location where you could add all of your timers, rather than having to manually add into each function/method.

@johnbillion Possible to add qm/start/qm/stop onto a hook, and if there's no param (function name) provided, assume current_action()?

[johnbillion]

For now you'll need to manually call the actions (don't worry, I'm writing up some documentation for this feature), but some sort of automated measurements is a good idea and I'll look at it at a later date.

@crstauf Good idea, I like it. #309.

[crstauf]

@johnbillion has the documentation for these functions been created? I'm attempting to implement, but doesn't look like lapping is being displayed in the output?

[crstauf]

Addressed in #337 (comment)