Hi,
As I already said, I don't see any technical issues with the patch.
I don't like it very mach, but it looks robust, and I don't object about it.
Thanks. Dmitry.
On 10/14/2011 10:08 PM, Arnaud Le Blanc wrote:
Hi,
I've already posted this patch and it has since been reviewed and improved.
I'm re-posting it for discussion before eventually commiting it.
The ternary operator always copies its second or third operand, which is very
slow compared to an if/else when the operand is an array for example:
$a = range(0,9);
// this takes 0.3 seconds here:
for ($i = 0; $i< 5000000; ++$i) {
if (true) {
$b = $a;
} else {
$b = $a;
}
}
// this takes 3.8 seconds:
for ($i = 0; $i< 5000000; ++$i) {
$b = true ? $a : $a;
}
I've tried to reduce the performance hit by avoiding the copy when possible
(patch attached).
Benchmark:
Without patch: (the numbers are the time taken to run the code a certain
amount of times)
$int = 0;
$ary = array(1,2,3,4,5,6,7,8,9);
true ? 1 : 0 0.124
true ? 1+0 : 0 0.109
true ? $ary : 0 2.020 !
true ? $int : 0 0.103
true ? ${'ary'} : 0 2.290 !
true ?: 0 0.091
1+0 ?: 0 0.086
$ary ?: 0 2.151 !
${'var'} ?: 0 2.317 !
With patch:
true ? 1 : 0 0.124
true ? 1+0 : 0 0.195
true ? $ary : 0 0.103
true ? $int : 0 0.089
true ? ${'ary'} : 0 0.103
true ?: 0 0.086
1+0 ?: 0 0.159
$cv ?: 0 0.090
${'var'} ?: 0 0.089
The array copying overhead is eliminated. There is however a slowdown in some
of the cases, but overall there is no completely unexpected performance hit as
it is the case currently.
What do you think ? Is there any objection ?
Best regards,
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