#46926 [Com]: mktime() is slow when it gets very small 3rd argument

From: Date: Tue, 10 Mar 2009 18:55:54 +0000
Subject: #46926 [Com]: mktime() is slow when it gets very small 3rd argument
References: 1  Groups: php.bugs 
Request: Send a blank email to php-bugs+get-134576@lists.php.net to get a copy of this message 
 ID:               46926
 Comment by:       mmcnicklebugs at googlemail dot com
 Reported By:      for-bugs at hnw dot jp
 Status:           Assigned
 Bug Type:         Performance problem
 Operating System: *
 PHP Version:      5.2.8
 Assigned To:      derick
 New Comment:

[PATCH]

I've created a patch [1] which resolves the performance issue. 

do_range_limit() did a naïve factoring approach when passed a negative
offset. I've implemented the same factoring that is used for positive
values. All the tests pass.

The patch is against CVS 5.3.

[1] http://whompbox.com/patches/php/tm2unixtime.patch

-- Martin McNickle


Previous Comments:
------------------------------------------------------------------------

[2008-12-22 14:01:51] for-bugs at hnw dot jp

I'm sorry, reproduce code depends on my timezone. Replace code as
below:

  $unixtime = mktime(9,0,-2147483647,1,1,1970);

to

  $unixtime = gmmktime(0,0,-2147483647,1,1,1970);

and

  $unixtime = mktime(9,0,2147483646,1,1,1970);

to

  $unixtime = gmmktime(0,0,2147483646,1,1,1970);

------------------------------------------------------------------------

[2008-12-22 13:55:06] for-bugs at hnw dot jp

Description:
------------
when it gots very small 3rd argument, mktime() performs 1000 times
slower than ordinary case.


Reproduce code:
---------------
<?php

$mt0 = microtime(true);
for($i=0;$i<10;$i++){
  $unixtime = mktime(9,0,-2147483647,1,1,1970);
}
$mt1 = microtime(true);
for($i=0;$i<10;$i++){
  $unixtime = mktime(9,0,2147483646,1,1,1970);
}
$mt2 = microtime(true);
printf("%.6f\n%.6f\n", $mt1-$mt0, $mt2-$mt1);

// This will output
// 5.139942
// 0.000707
// on my machine

Actual result:
--------------
see reproduce code


------------------------------------------------------------------------


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