smart_str performance

Switched it to avoid a copy on convert_to_string(). Performance in PHP5
now beats the previous version.

-Sterling

This was a email I sent to Rasmus and another co-worker a while ago and forgot
to post the question to the list. I just saw a commit converting zlib to
smart_str and figured I would send it now.

Comments?

Brian

---

I think I found what you were looking for yesterday. implode has change
between 4.3 and 4.2. 4.2 does the double pass while 4.3 has changed to use a
new smart_str struct with smart_str_appendl function (a struct and function
calls around what I was doing in my extension). I decided to run some
quick tests and here is what I have found:

for ( $i=0; $i < $count; $i++ ) {
$arr[] = rand_string_function(); // 12 characters
}

$start = gettimeofday();
$str = implode( "", $arr );
$end = gettimeofday();
printf( "%8.8d: %8.8f\n", $count, time_diff( $start, $end ) );

give this output:

4.3:
1: 0.00005100
2: 0.00002800
5: 0.00003700
10: 0.00006000
100: 0.00045600
1000: 0.00478600
10000: 0.06507500
100000: 1.71620700

4.2:
1: 0.00004700
2: 0.00002500
5: 0.00002800
10: 0.00004000
100: 0.00022400
1000: 0.00240700
10000: 0.03677200
100000: 0.37068200

While below 10 items I am sure it is hard to tell the difference, but it is
slower in all cases. Any clue why one item is slower than two or even five?

Brian
--
"First they ignore you, then they laugh at you,
then they fight you, then you win."
- Gandhi