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?
When you ran your comparison tests you ran them using the same server I 
presume?
Are you restarting the services i.e. Apache/PHP-FPM between each test?

Rich