PHP - Any Other Way Then Usleep?

Hi all,

I post a strange behavior that could be reproduced (at least on apache2+php5).
I don't know if I am doing wrong but let me explain what I try to achieve.

I need to send chunks of binary data (let's say 30) and analyze the average Kbit/s at the end :

I sum each chunk output time, each chunk size, and perform my Kbit/s calculation at the end.

Code: [Select]
<?php

// build my binary chunk
$var= '';
$o=9000;
while($o--)
{
$var.= "testtest";
}

// get the size, prepare the memory.
$size = strlen($var);
$tt_sent = 0;
$tt_time = 0;

// I send my chunk 30 times
for ($i = 0; $i < 30; $i++)
{
// start time
$t = microtime(true);
echo $var."\n";
ob_flush();
flush();
$e = microtime(true);
// end time
// the difference should reprenent what it takes to the server to 
// transmit chunk to client right ?

// add this chuck bench to the total
$tt_time += round($e-$t,4);
$tt_sent += $size;
}

// total result
echo "\n total: ".(($tt_sent*8)/($tt_time)/1024)."\n";

?>

In this example above, it works so far ( on localhost, it oscillate from 7000 to 10000 Kbit/s through different tests).

Now, let's say I want to shape the transmission, because I know that the client will have enough of a chunk of data to process for a second.

I decide to use usleep(1000000), to mark a pause between chunk transmission.

Code: [Select]
<?php

// build my binary chunk
$var= '';
$o=9000;
while($o--)
{
$var.= "testtest";
}

// get the size, prepare the memory.
$size = strlen($var);
$tt_sent = 0;
$tt_time = 0;

// I send my chunk 30 times
for ($i = 0; $i < 30; $i++)
{
// start time
$t = microtime(true);
echo $var."\n";
ob_flush();
flush();
$e = microtime(true);
// end time
// the difference should reprenent what it takes to the server to 
// transmit chunk to client right ?

// add this chuck bench to the total
$tt_time += round($e-$t,4);
$tt_sent += $size;

usleep(1000000);
}

// total result
echo "\n total: ".(($tt_sent*8)/($tt_time)/1024)."\n";

?>

I am doing something wrong ? Does the buffer output is not synchronous ?

Thanks a Lot


Nunja

In one of my servers when ever I call sleep or usleep functions my script sleeps and never wakes up,
Any suggestion on what can cause the issue?
my php -v output:
Code: [Select]
PHP 5.2.17 (cli) (built: Jan 24 2012 20:49:48)
Copyright (c) 1997-2010 The PHP Group
Zend Engine v2.2.0, Copyright (c) 1998-2010 Zend Technologies
    with the ionCube PHP Loader v4.0.12, Copyright (c) 2002-2011, by ionCube Ltd.