PHP Optimization

PHP Optimization
by Dave Jesch - SpectrOMTech.com
OC WordCamp - June 7, 2014
How to make your code run faster

There will be code.
Warning:
© 2014 SpectrOMTech.com. All Rights Reserved.

Optimization
Dave Jesch, Lifetime Geek
➔1.0 Web Applications
➔Sales Conversion Plugins
➔eCommerce Solutions
Principal, SpectrOMTech.com

Mastering Security & Optimization...

1. How to Measure Improvement
2. Basic Optimization Techniques
3. Code Examples
Today’s Goals:

Secret Behind Optimization

1. Ways to Measure Outcome

What are we Measuring?
● Speed
● Memory
● Code simplification / maintenance

Number of Operations
O(n) notation is used to express the worst case
order of growth of an algorithm.
How an algorithm’s worst-case performance changes as
the size of the data set it operates on increases.
http://www.perlmonks.org/?node_id=227909

microtime()
http://us1.php.net/manual/en/function.microtime.php
memory_get_usage()
http://us1.php.net/manual/en/function.memory-get-usage.php
XDebug Profiler
http://www.xdebug.org/docs/profiler
Measuring Tools

2. Let’s make your code Awesome!

General Optimizations (1 of 7)
● Upgrade!
● 'string' is not the same as "string".
[2.62 : 3.78 @10,000,000]
● Use built-in functions, especially for arrays and strings.
array_column()/array_replace()/implode()/
explode(), etc.

● Identity 1===1 vs. Equality '1' == 1
[1.63 : 3.72 @10,000,000]
● Shift (n >> 1), not divide (n / 2)
[2.34 : 2.75 @10,000,000]
● Don’t make needless copies.

● Use reference operator $x = &$array['key']
[1.95 : 2.01 @10,000,000]
● unset large arrays when no longer needed.
● echo $a,$b; faster than echo $a.$b;
[1.11 : 2.48 @1,000,000]

● Avoid @ error control operator.
● Pre increment ++$i faster than post increment $i++
[0.95 : 1.05 @10,000,000]
● "foreach" for arrays is better than "for"
[1.38 : 4.35 @100,000]

● Initialize! using undefined variables is slower than pre-
initialized variables.
[0.82 : 4.41 @10,000,000]
● Don’t global unless you use it.
[1.82 : 2.01 @10,000,000]
● switch is faster than if (…) elseif (…) ...

● !isset($foo{5}) faster than strlen($foo) < 5
[0.26 : 0.84 @10,000,000]
● str_replace() faster than preg_replace()
strtr() faster than str_replace()
[0.47 : 0.49 : 1.05 @100,000]

● "{$var}" is faster than sprintf()
[2.19 : 6.87 @10,000,000]
● incrementing global var slightly slower than a local var
[8.98 : 9.09 @100,000,000]
● use ctype_alnum(), ctype_alpha() and
ctype_digit() over regex

3. Examples:

Bubble Sort
Optimized: O(n^2) Best case: O(n)
$len = count($arr);
for ($i = 0; $i < $len; ++$i) {
$swapped = false;
for ($j = 0; $j < $len - 1; ++$j) {
if ($arr[$i] < $arr[$j]) {
$x = $arr[$i];
$arr[$i] = $arr[$j];
$arr[$j] = $x;
$swapped = true;
}
}
if (!$swapped)
break;
}
Non-Optimized: O(n^2)
for ($i = 0; $i < count($arr); $i++) {
for ($j = 0; $j < count($arr) - 1; $j++) {
if ($arr[$i] < $arr[$j]) {
$x = $arr[$i];
$arr[$i] = $arr[$j];
$arr[$j] = $x;
}
}
}

Reuse Function Results
Non-Optimized:
if (get_option('some_setting') > 0)
$var = get_option('some_setting');
else
$var = 0;
Optimized:
// use option or set to 0 if option not set
if (($var = get_option('some_setting')) < 0)
$var = 0;

Iterating Arrays
Non-Optimized:
// iterate through an array
foreach ($aHash as $key => $val) {
call_func($aHash[$key]);
}
12.01 seconds @10,000,000
Optimized:
// iterate through an array
while (list($key) = each($aHash)) {
call_func($aHash[$key]);
}
0.73 seconds @10,000,000

For Loops
Non-Optimized:
// loop through all elements of array
for ($i = 0; $i < count($a); ++$i) {
// do something
}
Optimized:
// loop through all elements of array
for ($i = 0, $c = count($a); $i < $c; ++$i) {
// do something
}

Latency Solutions: Transients
// get data from transient
if (($value = get_transient('my_transient_name')) === false) {
// nothing in transient, get from remote API
$value = wp_remote_get('http://some-domain.com', $args);
// save data from API in transient
set_transient('my_transient_name', $value, $expiration);
}

Ordering of Conditions
if (fastest() || fast() || slowest()) {
// some code here
}
________________________________________________________________
if (op1() && op2() && op3()) {
// more code
}

Code Optimized!
1. Practice, practice, practice
2. Always more to learn
3. Balancing act
4. Art form meets science

WP Geek Lab- Give back to WordPress.org
Alone we can do so little; together we can do so much. - Helen Keller
Connect with us at Hello@SpectrOMTech.com for more info.
write code...fix bugs...hangout...talk geek...

More References
http://phplens.com/lens/php-book/optimizing-debugging-php.php
http://alexatnet.com/articles/php-micro-optimization-tips
http://www.mdproductions.ca/guides/50-best-practices-to-optimize-php-code-
performance
http://php100.wordpress.com/2009/06/26/php-performance-google/

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