----- Original Message -----
From: "Jon Anderson" <jon@xxxxxxxxxxxxxxxxxx>
To: <php-general@xxxxxxxxxxxxx>
Cc: "Al" <news@xxxxxxxxxxxxx>
Sent: Sunday, September 10, 2006 9:16 PM
Subject: Re: Re: Newbie question about <?= ?>
Al wrote:
Structurally, there is a far better way to compile your html pages. This
approach is easier to design and debug and it is faster since it sends
one complete packet instead of one for every short tag. And, it saves
using ob_start() and ob_flush().
Consider:
$report= '';
$report .= function() [or whatever]
..... repeat as necessary to assemble your complete page.
Then simply
echo $report;
I thought I'd look into this, because I'm a bit of a performance nut - I
like my code to run as fast as possible at all times. I wrote up a quick
buffer v.s. direct "benchmark" for this, and the winner is clear: direct
output is much faster. (If my example below isn't what you meant, please
let me know. I'm always happy to hear new ways to improve my code.)
Best of 3 runs with apache bench (concurrency 10, 1000 requests total):
Direct output: 582 requests a second
Buffer var: 286 requests a second
I believe the margin would get wider with real-world usage, as the buffer
variable would increase in size. My test code is copied below.
jon
--- "Direct output": testecho.php ---
<html>
<head>
<style type="text/wastespacetosimulateastylesheet">
style1 {
a = 1;
b = 2;
c = 3;
d = 4;
e = 5;
f = 6;
}
style2 {
a = 1;
b = 2;
c = 3;
d = 4;
e = 5;
f = 6;
}
style3 {
a = 1;
b = 2;
c = 3;
d = 4;
e = 5;
f = 6;
}
style4 {
a = 1;
b = 2;
c = 3;
d = 4;
e = 5;
f = 6;
}
</style>
</head>
<body><table>
<?php for ($x=0;$x<1000;$x++) { ?>
<tr><td>X is <?= $x ?></td></tr>
<?php } ?>
</table></body>
</html>
--- "Buffered output": testbuffer.php ---
<?php
$buffer = '
<html>
<head>
<style type="text/wastespacetosimulateastylesheet">
style1 {
a = 1;
b = 2;
c = 3;
d = 4;
e = 5;
f = 6;
}
style2 {
a = 1;
b = 2;
c = 3;
d = 4;
e = 5;
f = 6;
}
style3 {
a = 1;
b = 2;
c = 3;
d = 4;
e = 5;
f = 6;
}
style4 {
a = 1;
b = 2;
c = 3;
d = 4;
e = 5;
f = 6;
}
</style>
</head>
<body><table>';
for ($x=0;$x<1000;$x++) {
$buffer .= "<tr><td>X is $x</td></tr>";
}
$buffer .= '</table></body>
</html>';
echo $buffer;
?>
--
In my message I was careful to mention that stepping in and out of PHP was
good 'for the longer invariable parts of immutable HTML'. What could be
considered 'longer' is certainly a matter discussion, your results prove
that this is not long enough. Notice that when the parser finds the '<?=',
it converts it into the equivalent of "<? echo", thus, though the echo is
not explicitly there, from the parser on is as if it were. Then, since you
have an echo, why not use it for all of the output? The equivalent to
what I showed as the second best, which would be the first best with
'shorter' strings would be the following:
for ($x=0;$x<1000;$x++) {
echo ' <tr><td>X is ' , $x , '</td></tr>';
}
Can you try and time that one so we have comparable results? This one
should be second best:
for ($x=0;$x<1000;$x++) {
echo "<tr><td>X is $x</td></tr>";
}
Back again to what would be 'longer', well, in your example, the whole
header, up to the loop itself should be faster if sent out of PHP.
Likewise, you could echo $buffer right after the loop, drop out of PHP and
send the footer as plain HTML. This, of course, is harder to time since it
happens only once. I admit though that I did time the options I listed and
on the 'dropping in and out of PHP' I'm relying on the PHP manual ( see
http://www.php.net/manual/en/language.basic-syntax.php, the first paragraph
after the examples) and the source of the lexical scanner, which supports
that, though your numbers do contradict it. Interesting.
Satyam
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