RE: Significant response time delays between 8.0 and 8.1

Thanks Rich.
Answers below, prefixed by A:. Also added a table of differences between the PHP versions.
Cheers
...Steve


-----Original Message-----
From: richard gray <[email protected]> 
Sent: Tuesday, December 19, 2023 7:43 PM
To: Steve Parry <[email protected]>; [email protected]
Subject: Re: Significant response time delays between 8.0 and 8.1

On 18/12/2023 21:40, Steve Parry wrote:
> Hi Everyone.
>
> I’m a hobby programmer, so please be kind😊
>
> I’m investigating a performance degradation that I have between PHP8.0 
> and PHP8.1. I see a couple of similar issues being raised but no 
> resolutions that I’ve found.
>
> In my live WordPress system I have HTML/Java scripts that make 
> multiple ajax calls to PHP scripts on the remote hosted web server. On 
> upgrading to 8.1 the number of ajax calls failing with timeout 
> increased dramatically by a factor of between 4 to 8 depending on the 
> frequency of calls at any one time.
>
> Examination of a comparison showed scripts were taking up to 15 
> seconds under PHP8.1 compared to 1-2 seconds on PHP8.0.
>
> To isolate the issue I created a simple (non-WordPress) web script 
> that on the click of an icon uses ajax to send a retrieve request to a 
> server script. The server test script simply immediately returns one 
> piece of hardcoded dummy jSON data with no processing.
>
> Based on the Chrome debugger Network tab, the time of the network 
> calls triggered from the test script under PHP8.0 are a response of 
> around 25mS.  Under 8.1 the timings are average 92mS. A factor of 
> about 3.7 slower under 8.1. This has been consistent on two separate 
> servers.
>
> My conclusion at this point is that my test setup is reflecting the 
> same (or worse) time delay factor between PHP8.1 and PHP8.0  as I am 
> having on the full site. As my test setup is pure HTML/Javascript and 
> PHP on the server I think this might be an issue with PHP8.1.
>
> Any advice or assistance is keenly welcomed! Thank you in advance.
>
> Happy to share my scripts and the URL to the test script.
>
> Cheers
>
> …Steve
>
>
Hi Steve

Seems strange to me.. a couple of questions...

Are the 2 PHP versions configured exactly the same? For example do both have opcache enabled?
A: Yes. Zend OPCache running on both.

When you ran your comparison tests you ran them using the same server I presume?
A: Yes.

Are you restarting the services i.e. Apache/PHP-FPM between each test?
A: No - The server is a shared hosting server - I have no control over restarting services. The issue is demonstrated by changing the PHP version in the CPanel using MultiPHP Manager - as many times as you like! 

Rich

I did a compare between the PHPInfo from PHP8.0 and PHP8.1 and found the following that might have an impact. 
As I really don't understand these parameters very well, could you suggest any which may have an impact that I could change? (Not sure how well a text only email will format this, but here we go!):

Parameter		PHP8.0		PHP8.1
Loaded Configuration 			File path error in 8.1?
allow_url_fopen  	Off		On
display_startup_errors 	Off		On
Expose_php 		Off		On
Log_errors 		On		Off
Mail.aff_x_header 	On		Off
Max_execution time 	600/30		 600/600
max_input_time 	120/60	 	120/120
memory_limit 		1024/128	1024/1024
output_buffering 	no value	 0
post_max_size 		512/2		512/512
variables_order 	GPCS		EGPCS
zend.assertions 		-1		1
PDO drivers				Additional PDO drivers seen
PDO_ODBC section 	No PDO_ODBC	PDO_ODBC section
Pgsql section in 8.1	No Pgsql	Pgsql section
session.cookie_httponly	 no value	 0
session.gc_divisor 	0		100
session.gc_probability 	0	 	1
url_rewriter.tags	a=href		area=href, frame=src, input=src, form=fakeentry	form=
Zend OPCache 		running	 	running
Environment section 			heaps more Variables defined 
PHP Variables section 			heaps more Variables defined

Many thanks!
Cheers
...Steve