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IDProjectCategoryView StatusDate SubmittedLast Update
0002407XdebugUncategorizedpublic2026-02-27 05:062026-03-23 19:13
ReporterSoul--Reaver Assigned Toderick  
PrioritynormalSeveritymajorReproducibilityalways
Status assignedResolutionopen 
Platformx64OSWindows 11OS Version25H2
Product Version3.5.1 
Summary0002407: Performance issues with 3.5.1 vs 3.4
Description

I updated my PHP and Xdebug today.
Some performance testing scripts i have suddenly saw issues.
Saw the other tickets concerning performance issues and can say 3.5.1 is better compared to 3.5.0 but not to earlier versions.

CPU: AMD 5700G
All of this was done on PHP 8.3.30 since Xdebug 3.4.7 was not available for PHP 8.5.x.

Steps To Reproduce

I've attached a simple script that loops through if statements using == and === and measures performance between them. Nothing special but it allows a stable performance comparison.

Xdebug 3.4.7:
== with matching strings took 1.211257 seconds
== with non-matching strings took 1.252350 seconds
=== with matching strings took 1.295035 seconds
=== with non-matching strings took 1.309487 seconds

Xdebug 3.5.0:
== with matching strings took 24.441501 seconds
== with non-matching strings took 24.591401 seconds
=== with matching strings took 24.634848 seconds
=== with non-matching strings took 24.689718 seconds

Xdebug 3.5.1:
== with matching strings took 7.929764 seconds
== with non-matching strings took 8.108500 seconds
=== with matching strings took 8.093506 seconds
=== with non-matching strings took 8.169023 seconds

TagsNo tags attached.
Attached Files
test_==_===.php (973 bytes)    
<pre>
<?php
$time_start = microtime(true);

for ( $i = 0; $i < 10000000; ++$i )
{
   $results = ('string' . $i) == ('string' . $i);
}

$time_end = microtime(true);
printf("== with matching strings took %f seconds\n", $time_end - $time_start);

$time_start = microtime(true);

for ( $i = 0; $i < 10000000; ++$i )
{
   $results = ('string' . $i) == ('string' . ($i + 1));
}

$time_end = microtime(true);
printf("== with non-matching strings took %f seconds\n", $time_end - $time_start);

$time_start = microtime(true);

for ( $i = 0; $i < 10000000; ++$i )
{
   $results = ('string' . $i) === ('string' . $i);
}

$time_end = microtime(true);
printf("=== with matching strings took %f seconds\n", $time_end - $time_start);

$time_start = microtime(true);

for ( $i = 0; $i < 10000000; ++$i )
{
   $results = ('string' . $i) === ('string' . ($i + 1));
}

$time_end = microtime(true);
printf("=== with non-matching strings took %f seconds\n", $time_end - $time_start);
?>
</pre>
test_==_===.php (973 bytes)   
Operating SystemWindows 11 25H2
PHP Version8.3.20-8.3.29

Activities

derick

2026-03-23 14:15

administrator   ~0007472

I'm glad to see that Xdebug 3.5.1 is again much faster than 3.5.0 — but it is not good to see it is still so much slowed than 3.4.x.

Could you run your benchmark again after setting xdebug.control_socket=off (https://xdebug.org/docs/all_settings#control_socket) in your php.ini file?

Soul--Reaver

2026-03-23 19:13

reporter   ~0007481

See the results below.

Xdebug 3.4.7:
== with matching strings took 1.159194 seconds
== with non-matching strings took 1.228071 seconds
=== with matching strings took 1.246445 seconds
=== with non-matching strings took 1.268770 seconds

Xdebug 3.5.0:
== with matching strings took 1.376464 seconds
== with non-matching strings took 1.431510 seconds
=== with matching strings took 1.488096 seconds
=== with non-matching strings took 1.515451 seconds

Xdebug 3.5.1:
== with matching strings took 1.353204 seconds
== with non-matching strings took 1.419595 seconds
=== with matching strings took 1.487886 seconds
=== with non-matching strings took 1.515623 seconds

Issue History

Date Modified Username Field Change
2026-02-27 05:06 Soul--Reaver New Issue
2026-02-27 05:06 Soul--Reaver File Added: test_==_===.php
2026-03-23 14:15 derick Assigned To => derick
2026-03-23 14:15 derick Status new => feedback
2026-03-23 14:15 derick Note Added: 0007472
2026-03-23 19:13 Soul--Reaver Note Added: 0007481
2026-03-23 19:13 Soul--Reaver Status feedback => assigned