0002395: Severe performance degredation on Windows - MantisBT

ID	Project	Category	View Status	Date Submitted	Last Update
0002395	Xdebug	Uncategorized	public	2026-01-09 14:53	2026-02-03 15:37

Reporter	kieranfj	Assigned To
Priority	normal	Severity	minor	Reproducibility	always
Status	closed	Resolution	fixed
Platform	Windows	OS	Windows 11	OS Version	24H2 26100.7392
Product Version	3.5.0
Fixed in Version	3.5.1

Summary	0002395: Severe performance degredation on Windows
Description	I have a WAMPServer based setup locally with various PHP versions stretching back to 8.0. Xdebug in daily use across multiple separate projects. I switch PHP versions semi regularly. Primarily 8.3/8.4 Previous versions worked without any noticeable or unacceptable delay (e.g xdebug off = 4 seconds to process, xdebug on 5 seconds) across any of the PHP version. Recently Xdebug 3.5.0 was released via the WAMPServer page https://wampserver.aviatechno.net/ and i installed it, which then updated all the PHP versions installed for me as intended. However i have found that when running 3.5.0 (.dll is loaded, apache service started etc) that a process that typically takes 4-6 seconds, inflates to 40-50 seconds doing the same thing. If i switch back the versions by changing the .dll being loaded in php.ini to the previous version (3.4.7, or if i got to PHP8.0 3.4.4 The general way of working this out was to put simple micro timestamp start - micro timestamp stop before and after method execution of my code, pushed into a generic debug log of our own creation. Attached is a debug dump that might not make sense, but it has micro time just before some file content
Steps To Reproduce	Start wamp PHP 8.4 with 3.5.0 Do some heavy xml checking/processing Do the same with 3.4.4 Compare the time it takes on both.
Additional Information	php_xdebug-3.4.4-8.4-ts-vs17-x86_64 - 4-6 seconds php_xdebug-3.5.0-8.4-ts-vs17-x86_64 - 40-50 seconds xdebug.mode = develop xdebug.log_level = 7 I dont change xdebug settings between the versions, i have changed php.ini to point at the different dll's and restarted the apache service to pick it up The process is basically: Request comes in Bunch of login, session check, security etc before we hit this specific process We run 4 methods that i have put debug lines around to track microtime before and after and output the result We have 20 files We file_get_contents each file in turn - files contain XML We simplexml_load_string the content We then check for xml paths and some small quick loops (//button //grid //field etc) Output microtime before and after each mini loop Output microtime for the whole method Output microtime for other methods afterwards which also indicate each log file should be the same incoming request with the same file being loaded in the same sequence. The only manual alteration to the files i have made is to remove some folder structure information for privacy reasons
Tags	No tags attached.

Operating System	Windows
PHP Version	8.4.10-8.4.19

derick 2026-01-14 11:06 administrator ~0007445	Could you try setting `xdebug.control_socket` to `off`, and see if that alleviates the slow down/timeout?

kieranfj 2026-01-14 13:53 reporter ~0007447	Hi Derick Since posting the issue, i have managed to take a portion of our internal code and put it into small, self contained test project. It exhibits the slow down, but its not a full 30-40s portion like the original .txt files show as its running significantly less code, but the 10x performance hit between runs is evident. For example With 3.4.4 it is 0.2 seconds, with 3.5.0 it is 2 seconds to provide context to the below. I would provide the code it but its internal code and i don't think you'd what to start working what/why we're doing what we're doing unless i can reduce the test further. Anyway, for that reduced test: Xdebug 3.5.0 With xdebug.control_socket to off Starting performance test... Execution time: 0.15103507041931 seconds Finished performance test... With xdebug.control_socket commented out: Starting performance test... Execution time: 1.9091730117798 seconds Finished performance test... Same code, same test, apache service restarted in between php.ini changes. Just for comparison: With xdebug 3.4.4 With xdebug.control_socket to off Starting performance test... Execution time: 0.14583110809326 seconds Finished performance test... With xdebug.control_socket commented out: Starting performance test... Execution time: 0.14948511123657 seconds Finished performance test... On the original full test (work machine) 3.5.0 i did a quick run of our code (so it might not be 100% apples to apples) With xdebug.control_socket to off About 9 seconds With xdebug.control_socket commented out: about 47 seconds Thanks Kieran

derick 2026-01-22 16:24 administrator ~0007453	The fix for this issue, merged through https://github.com/xdebug/xdebug/pull/1060, should alleviate the need for turning the control sockets off again on Windows. You'll find this in the (upcoming) 3.5.1 release.

derick 2026-01-22 16:27 administrator ~0007455	FWIW, you can try out that development version with the binarires at https://github.com/xdebug/xdebug/actions/runs/21256100508#artifacts