PHP ErrorException creation takes a long time - php

Question

After profiling a PHP script, I found that creating an exception appears to take a huge amount of time:
%Time Real User System Calls secs/call Name
100.0 0.00 3448.05 0.00 8.89 0.00 1.81 1 0.0000 3448.0543 main
64.7 2230.28 2230.28 0.02 0.02 0.00 0.00 892 2.5003 2.5003 sleep
35.1 0.01 1211.84 0.00 8.16 0.00 1.49 1001 0.0000 1.2106 do_process
34.7 986.81 1197.34 2.59 2.60 1.18 1.18 1330 0.7420 0.9003 file_get_contents
6.1 0.00 210.53 0.00 0.01 0.00 0.01 28 0.0000 7.5191 __lambda_func
6.1 210.53 210.53 0.01 0.01 0.01 0.01 28 7.5191 7.5191 ErrorException->__construct
0.4 0.00 13.47 0.01 5.21 0.00 0.18 206 0.0000 0.0654 do_check
0.4 13.15 13.15 5.08 5.08 0.15 0.15 402 0.0327 0.0327 preg_replace
So that's 7.5 seconds of real (not CPU) time per ErrorException->__construct. I'm looking for ideas on how to improve this!
Relevant code:
set_error_handler(
create_function(
'$severity, $message, $file, $line',
'throw new ErrorException($message, $severity, $severity, $file, $line);'
)
);
$opts = array(
'http' => array(
'method' => 'GET',
'timeout' => 60
)
);
$ctx = stream_context_create($opts);
try {
$this->data = file_get_contents($url, false, $ctx);
} catch (Exception $e) {
# The set_error_handler call ensures that we arrive here on any type
# of error.
$this->data = '';
if(preg_match('/HTTP\/1.[0|1] 4[0-9][0-9] /', $e->getMessage()) == 1) {
return 404;
} else if(strpos($e->getMessage(), "php_network_getaddresses: getaddrinfo failed") !== false) {
return 1000;
} else {
$this->message = $e->getMessage();
return -1;
}
}
Even if there's no obvious answer, I'd like to understand what factors could influence the real time to be so large. My understanding is that the constructor doesn't include time for the file_get_contents call itself or the catch clause, so can't really think of a good reason (other than trying to allocate a huge amount of memory) why this should be slow.

Answer 1

You are using an oldschool lambda function created with a call to create_function(). Is there a reason for this? Because the way that function operates is slow. You pass it a STRING with the code of the function, but that string has to be evaluated during runtime. There is no way the opcode cache could cache that code for you.

Answer 2

After quite a bit more testing, the problem appears to be with how APD profiling measures the elapsed time. If I put any other statement inside the error handler before throw, the profiler counts all the elapsed time against that, as mentioned in my comment.
Therefore, I'm convinced that the high elapsed time is because the profiler actually includes elapsed time from file_get_contents.
I tried using XHProf instead, and this seems to give more correct results. At least, it shows the ErrorException->__construct as taking only minimal elapsed time.