Tools to visually analyze memory usage of a PHP app.

Question

Is there anything out there freeware or commercial that can facilitate analysis of memory usage by a PHP application? I know xdebug can produce trace files that shows memory usage by function call but without a graphical tool the data is hard to interpret.

Ideally I would like to be able to view not only total memory usage but also what objects are on the heap and who references them similar to Jprofiler.

Answer 1

A graphical tool for xdebug output is KCacheGrind.

Answer 2

Try webgrind. It gives you the profiling of CacheGrinder in an easy to read, browser based format. I'm on a Mac and it has made profiling a breeze.

Answer 3

phpDesigner 2008 can debug and benchmark websites using xdebug and KCacheGrind. It also has a built-in monitor.

Answer 4

I came across the same issue recently, couldn't find any specific tools unfortunately.

But something that helped was to output the xdebug trace in human readable format with mem deltas enabled (an INI setting, xdebug.show_mem_deltas or something I think?). Then run sort (if you are on *nix) on the output:

sort -bgrk 3 -o sorted.txt mytracefile.xt

That sorts on the third col, the mem deltas. You can also sort on the second column, in which case you can find the line at which your app uses the most memory in total.

Of course, this can't detect when an object's memory usage only creeps up in small increments but ends up using a lot of memory overall. I have a fairly dumb method that attempts to do this using a combination of object iteration and serialization. It probably doesn't equate exactly to memory usage, but hopefully gives an idea of where to start looking. Bear in mind it will use up memory itself, and also has not been extensively tested, so buyer beware:

function analyzeMem($obj, $deep=false)
{
    if (!is_scalar($obj))
    {
     $usage = array('Total'=>strlen(serialize($obj)));
     while (list($prop, $propVal) = each($obj)) 
     {
      if ($deep && (is_object($propVal) || is_array($propVal)))
      {
       $usage['Children'][$prop] = analyzeMem($propVal);
      }
      else
      {
       $usage['Children'][$prop] = strlen(serialize($propVal));
      }
     }
     return $usage;
    }
    else
    {
     return strlen(serialize($obj));
    }
}

print_r(analyzeMem(get_defined_vars()));

Also, just got suggested this method by a colleague (cheers Dennis ;-) This hides the steps that are below 2 levels of indentation, you can quite easily see the points where the overall memory usage jumps up, and can narrow things down by increasing the indentation:

egrep '[0-9]+ (  ){1,2}-> ' mytracefile.xt

Answer 5

On http://www.xdebug.org/updates.php for Xdebug 2.0.4 they write in section "removed functions": "...Removed support for Memory profiling as that didn't work properly...". Hence xdebug wont be an option

Answer 6

Mhmm. I need to do some serious memory analyzing, too. I wonder if this link helps: http://derickrethans.nl/xdebug-and-tracing-memory-usage.html Have to test this tomorrow.