performance of the new output api

JFYI & SCNR,

I produced some synthetic numbers of the performance comparing the
new output control layer with the old one -- actually because I
expected the new code to be less efficient than the one we had.

I didn't have the chance to do this until now, because comparing
php-unicode with php-5.x would have been even more useless ;)

Anyway, running the script listed at the end of this message gave
me quite surprising results, and still leaves me suspicious:

Running in trunk with std-output-api:
mike@waldrapp:~/tmp/php-trunk-old-output$ ./sapi/cli/php ~/tmp/ob_bench.php
Running 50000 times with a 16383 bytes long string (' ...')

 0 -  0.000s:        0.6 /       0.6 MB

10000 - 0.172s: 168.3 / 178.2 MB
20000 - 0.340s: 335.9 / 355.5 MB
30000 - 0.506s: 503.5 / 532.8 MB
40000 - 0.671s: 671.2 / 710.2 MB
50000 - 0.836s: 838.8 / 887.5 MB

Cleaning up 25001 output handlers
Done, total time: 1.362s, peak mem: 838.8 / 887.5 MB

Running in current trunk with new-output-api:
mike@waldrapp:~/build/php-trunk-debug$ ./sapi/cli/php ~/tmp/ob_bench.php
Running 50000 times with a 16383 bytes long string (' ...')

 0 -  0.000s:        0.6 /       0.6 MB

10000 - 0.104s: 69.0 / 71.7 MB
20000 - 0.204s: 137.4 / 142.7 MB
30000 - 0.304s: 205.8 / 213.7 MB
40000 - 0.405s: 274.2 / 284.7 MB
50000 - 0.506s: 342.5 / 355.7 MB

Cleaning up 25001 output handlers
Done, total time: 0.740s, peak mem: 342.6 / 355.7 MB

Now the script:
<?php
ini_set("memory_limit", "2G");

function mib($b) {
return $b ? number_format($b/1024/1204, 1, ".", "'") : "?";
}

function mgu($r, $p = false) {
return mib($p ? memory_get_peak_usage($r) : memory_get_usage($r));
}

function obs($i) {
global $start;
fprintf(STDERR, "> %6d - %6.3fs: %10s /%10s MB\n",
$i,
microtime(true)-$start,
mgu(false), mgu(true)
);
}

$loop = @$argv[1] ?: 50000;
$data = @$argv[2] ?: str_repeat(" ", 0x3fff);

fprintf(STDERR, "Running %d times with a %d bytes long string ('%s...')\n",
$loop,
strlen($data),
substr($data, 0, 3)
);

$start = microtime(true);
for ($i = 0; $i < $loop; ++$i) {
ob_start();
echo $data;

 if (!($i % 10000)) {
     obs($i);
 }

 if ($i % 2) {
     `ob_flush()`;
 } elseif ($i) {
     `ob_end_clean()`;
 }

}
obs($i);

fprintf(STDERR, "\nCleaning up %d output handlers\n",
ob_get_level()
);
while(ob_get_level())
ob_end_clean();

fprintf(STDERR, "Done, total time: %6.3fs, peak mem: %s / %s MB\n",
microtime(true)-$start,
mgu(false, true), mgu(true, true)
);

Cheers,
Mike