来自：http://maettig.com/code/php/php-performance-benchmarks.php （非永久链接）
关于php程序执行性能的一个测试，转载至此备查与学习。
My PHP Performance Benchmarks
PHP version 5.2.17 is running on this server. The benchmarks are done live. Reload the page to get fresh numbers. You are free to use the source for whatever you want. Giving credits to me (Thiemo Mättig) would be nice.
Please note that these are micro benchmarks. Micro benchmarks are stupid. I created this comparison to learn something about PHP and how the PHP compiler works. This can not be used to compare PHP versions or servers.
Check if a String is empty
| Method | Undefined | Null | False | Empty string | String “0” | String “1” | Long string | Summary | Index |
|---|---|---|---|---|---|---|---|---|---|
if (!$var) |
2 ms | >0 ms | >0 ms | >0 ms | >0 ms | >0 ms | >0 ms | 4 ms | 133 |
if (empty($var)) |
>0 ms | 1 ms | 1 ms | 1 ms | 1 ms | >0 ms | >0 ms | 3 ms | 100 |
if ($var == "") |
2 ms | >0 ms | >0 ms | 1 ms | >0 ms | >0 ms | 38 ms | 43 ms | 1380 |
if ("" == $var) |
2 ms | >0 ms | >0 ms | 1 ms | >0 ms | >0 ms | >0 ms | 5 ms | 161 |
if ($var === "") |
2 ms | >0 ms | >0 ms | >0 ms | >0 ms | >0 ms | >0 ms | 3 ms | 109 |
if ("" === $var) |
2 ms | >0 ms | >0 ms | >0 ms | >0 ms | >0 ms | >0 ms | 4 ms | 119 |
if (strcmp($var, "") == 0) |
4 ms | 2 ms | 2 ms | 1 ms | 1 ms | 1 ms | 1 ms | 11 ms | 367 |
if (strcmp("", $var) == 0) |
3 ms | 2 ms | 2 ms | 1 ms | 1 ms | 1 ms | 1 ms | 11 ms | 361 |
if (strlen($var) == 0) |
3 ms | 1 ms | 1 ms | 1 ms | 1 ms | 1 ms | 1 ms | 9 ms | 294 |
if (!strlen($var)) |
3 ms | 1 ms | 1 ms | 1 ms | 1 ms | 1 ms | 1 ms | 9 ms | 276 |
My conclusion: In most cases, use empty() because it does not trigger a warning when used with undefined variables. Note that empty("0") returns true. Use strlen() if you want to detect "0". Try to avoid == at all because it may cause strange behaviour (e.g. "9a" == 9 returns true). Prefer === over == and !== over != if possible because it does compare the variable types in addition to the contents.
Compare two Strings
| Method | Equal | First character not equal | Last character not equal | Summary | Index |
|---|---|---|---|---|---|
$a == $b |
2 ms | 1 ms | 2 ms | 5 ms | 100 |
!strcmp($a, $b) |
4 ms | 3 ms | 4 ms | 10 ms | 196 |
strcmp($a, $b) == 0 |
4 ms | 4 ms | 7 ms | 14 ms | 269 |
strcmp($a, $b) === 0 |
6 ms | 5 ms | 6 ms | 18 ms | 336 |
strcasecmp($a, $b) === 0 |
13 ms | 4 ms | 9 ms | 26 ms | 490 |
My conclusion: Use what fits your needs.
Check if a String contains another String
| Method | Not found | Found at the start | Found in the middle | Found at the end | Summary | Index |
|---|---|---|---|---|---|---|
strstr($haystack, $needle) |
1 ms | 1 ms | 1 ms | 1 ms | 4 ms | 100 |
strpos($haystack, $needle) !== false |
1 ms | 1 ms | 1 ms | 1 ms | 4 ms | 100 |
strstr($haystack, $needle) !== false |
1 ms | 1 ms | 1 ms | 1 ms | 5 ms | 113 |
stristr($haystack, $needle) |
2 ms | 2 ms | 2 ms | 2 ms | 8 ms | 203 |
preg_match("/$needle/", $haystack) |
2 ms | 2 ms | 2 ms | 2 ms | 8 ms | 190 |
preg_match("/$needle/i", $haystack) |
2 ms | 2 ms | 2 ms | 2 ms | 8 ms | 199 |
preg_match("/$needle/S", $haystack) |
2 ms | 2 ms | 2 ms | 2 ms | 8 ms | 195 |
ereg($needle, $haystack) |
2 ms | 2 ms | 9 ms | 16 ms | 29 ms | 714 |
My conclusion: It does not matter if you use strstr() or strpos(). Use the preg…() functions only if you need the power of regular expressions. Never use the ereg…() functions.
Check if a String starts with another String
| Method | Not found | Found at the start | Found in the middle | Found at the end | Summary | Index |
|---|---|---|---|---|---|---|
strncmp($haystack, $needle, strlen($needle)) === 0 |
1 ms | 2 ms | 2 ms | 1 ms | 6 ms | 159 |
strncmp($haystack, "Test", 4) === 0 |
1 ms | 1 ms | 1 ms | 1 ms | 4 ms | 101 |
strncasecmp($haystack, $needle, strlen($needle)) === 0 |
2 ms | 2 ms | 2 ms | 1 ms | 6 ms | 166 |
strpos($haystack, $needle) === 0 |
1 ms | 1 ms | 1 ms | 1 ms | 4 ms | 100 |
substr($haystack, 0, strlen($needle)) === $needle |
2 ms | 2 ms | 2 ms | 2 ms | 6 ms | 169 |
strcmp(substr($haystack, 0, strlen($needle)), $needle) === 0 |
2 ms | 2 ms | 2 ms | 2 ms | 9 ms | 242 |
preg_match("/^" . preg_quote($needle, "/") . "/", $haystack) |
3 ms | 3 ms | 3 ms | 3 ms | 12 ms | 318 |
My conclusion: strpos() is very fast and can be used in almost all cases. strncmp() is good if you are looking for a constant length needle.
Check if a String ends with another String
| Method | Not found | Found at the start | Found in the middle | Found at the end | Summary | Index |
|---|---|---|---|---|---|---|
substr($haystack, strlen($haystack) - strlen($needle)) === $needle |
2 ms | 2 ms | 2 ms | 2 ms | 8 ms | 127 |
substr($haystack, -strlen($needle)) === $needle |
2 ms | 2 ms | 2 ms | 2 ms | 6 ms | 100 |
strcmp(substr($haystack, -strlen($needle)), $needle) === 0 |
2 ms | 2 ms | 2 ms | 2 ms | 9 ms | 140 |
preg_match("/" . preg_quote($needle, "/") . "$/", $haystack) |
3 ms | 4 ms | 3 ms | 3 ms | 14 ms | 222 |
My conclusion: Using substr() with a negative position is a good trick.
Replace a String inside another String
| Method | Not found | Found at the start | Found in the middle | Found at the end | Summary | Index |
|---|---|---|---|---|---|---|
str_replace($search, $replace, $subject) |
2 ms | 2 ms | 2 ms | 2 ms | 7 ms | 100 |
preg_replace("/$search/", $replace, $subject) |
3 ms | 3 ms | 3 ms | 3 ms | 12 ms | 173 |
preg_replace("/$search/S", $replace, $subject) |
3 ms | 3 ms | 3 ms | 3 ms | 12 ms | 170 |
ereg_replace($search, $replace, $subject) |
3 ms | 6 ms | 12 ms | 18 ms | 39 ms | 536 |
My conclusion: Never use the ereg…() functions.
Trim Characters from the Beginning and End of a String
| Method | Not found | Found at start | Found at end | Found at both sides | Summary | Index |
|---|---|---|---|---|---|---|
trim($string, ",") |
>0 ms | >0 ms | >0 ms | >0 ms | 1 ms | 100 |
preg_replace('/^,*|,*$/', "", $string) |
7 ms | 7 ms | 7 ms | 7 ms | 29 ms | 3725 |
preg_replace('/^,*|,*$/m', "", $string) |
12 ms | 12 ms | 12 ms | 12 ms | 47 ms | 6107 |
preg_replace('/^,+|,+$/', "", $string) |
>0 ms | >0 ms | >0 ms | >0 ms | 2 ms | 234 |
preg_replace('/^,+|,+$/m', "", $string) |
>0 ms | >0 ms | >0 ms | >0 ms | 2 ms | 230 |
preg_replace('/^,+/', "", preg_replace('/,+$/', "", …)) |
1 ms | 1 ms | 1 ms | 1 ms | 3 ms | 395 |
My conclusion: Always benchmark your regular expressions! In this case, with .* you also replace nothing with nothing which takes time because there is a lot of “nothing” in every string.
Split a String into an Array
| Method | Empty string | Single occurrence | Multiple occurrences | Summary | Index |
|---|---|---|---|---|---|
explode(",", $string) |
1 ms | 1 ms | 8 ms | 10 ms | 100 |
split(",", $string) |
1 ms | 2 ms | 38 ms | 41 ms | 416 |
preg_split("/,/", $string) |
2 ms | 2 ms | 12 ms | 16 ms | 160 |
preg_match_all('/[^,]+/', $string, $matches) |
2 ms | 3 ms | 18 ms | 24 ms | 242 |
My conclusion: Don’t use split(). It’s deprecated in PHP 5.3 and will be removed in PHP 6.
Loop a numerical indexed Array of Strings
| Method | Summary | Index |
|---|---|---|
for ($i = 0; $i < count($array); $i++) |
41 ms | 5811 |
for ($i = 0, $count = count($array); $i < $count; $i++) |
1 ms | 144 |
for ($i = count($array) - 1; $i >= 0; $i--) |
1 ms | 135 |
for ($i = count($array) - 1; $i >= 0; --$i) |
1 ms | 133 |
$i = count($array); while ($i--) |
1 ms | 100 |
My conclusion: count() is horribly slow. Always precalculate it, if possible.
Get Elements from an Array
| Method | Summary | Index |
|---|---|---|
$array[0] |
33 ms | 101 |
$array['key'] |
33 ms | 100 |
My conclusion: I like associative arrays.
Implode an Array
| Method | Summary | Index |
|---|---|---|
implode(" ", $array) |
5 ms | 100 |
"$array[0] $array[1] $array[2]" |
5 ms | 107 |
$array[0] . " " . $array[1] . " " . $array[2] |
5 ms | 104 |
sprintf("%s %s %s", $array[0], $array[1], $array[2]) |
10 ms | 207 |
vsprintf("%s %s %s", $array) |
12 ms | 251 |
My conclusion: String concatenation is a cheap operation in PHP. Don’t waste your time benchmarking this.
The single vs. double Quotes Myth
| Method | Summary | Index |
|---|---|---|
'contains no dollar signs' |
1 ms | 104 |
"contains no dollar signs" |
1 ms | 100 |
'$variables $are $not $replaced' |
1 ms | 101 |
"\$variables \$are \$not \$replaced" |
1 ms | 103 |
"$variables $are $replaced" |
7 ms | 1222 |
$variables . ' ' . $are . ' ' . $replaced |
9 ms | 1501 |
$variables . " " . $are . " " . $replaced |
9 ms | 1530 |
My conclusion: It does not matter if you use single or double quotes at all. The inclusion of variables has a measurable effect, but that’s independent from the quotes.