Operating System: Ubuntu 22.04.2 LTS
Kernel: Linux 5.15.0-60-generic
Architecture: x86-64
Zabbix 6.2.8
PHP 8.2.4
PostgreSQL 15.2 (Ubuntu 15.2-1.pgdg22.04+1)
Timescaledb 2.10.0

I see you are using almost the most recent software in any category. Thank you for testing out these components.

The patchs mentioned in strace.log are not standard paths of Zabbix frontend files.

1) Do you use stock Zabbix packages on Ubuntu 22?

apt list --installed | grep zabbix

2) Does Zabbix frontend is exposed to internet? If yes, could you try to reconfigure the web server port to listen on a different port (not use 80/443)? See if the CPU usage goes away.

1) yes I'm using packages from official repo:  https://repo.zabbix.com/zabbix/6.2/ubuntu jammy main

2) уes, frontend is exposed to internet. I can't reconfigure the web server port to listen on a different port, we use several services like grafana to integrate zabbix through api

ZBX-22582.patch.and.files.zip
Please patch your frontend files.

BTW, this is an interesting findings which can lower down CPU usage for different Zabbix builds. We will wait for your feedback.

Patch is only applicable for 6.2.x. "autoload.php" is a new file and must be placed in the /usr/share/zabbix

I've placed file "autoload.php" in /usr/share/zabbix. There is the same file in /usr/share/zabbix/vendor/, should I replace it?
I've also increased number of cores to 6 and still have problem with error like "(No such file or directory)" in strace output

efremovgv you do not need to replace vendor/autoload.php file, just place new one in same directory where zabbix.php file is. Also please apply the patch otherwise autoloader will not start. When applied there will be much less "No such file or directory", error still be present because local directory files also as modules directory files cannot be added to autoloader.php.

Also please apply the patch otherwise autoloader will not start what does it mean? I've just unzip ZBX-22582.patch.and.files.zip to /usr/share/zabbix and restart nginx and php-fpm

Go to /usr/share/zabbix directory, unzip and then execute git apply ZBX-22582.txt to apply changes to zabbix.php and index.php files.

When trying to apply the patch, the following error occurs. Is it necessary to change the path inside ZBX-22582.txt ?

Sorry patch was created as for Zabbix installed from git repository. Attached correct ZBX-22582.patch file, to apply go to /usr/share/zabbix directory and execute: patch < ZBX-22582.patch.

Is there such a patch for version 6.4.*? After upgrading from 6.2.9 to 6.4.2, the problem with user time cpu and total load returned

Hello Glafkon ,

Please download index.phpand zabbix.phpand overwrite to:

/usr/share/zabbix/zabbix.php
/usr/share/zabbix/index.php

This is tested and suitable for Zabbix 6.4.2. Let us know if CPU loading issue goes away.

Hello efremovgv , please download 6.2.9.index.phpand 6.2.9.zabbix.php and install the files on:

/usr/share/zabbix/zabbix.php
/usr/share/zabbix/index.php

This is suitable for Zabbix 6.2.9. Let us know if it solves CPU problem.

Thanks, I've alrady update on 6.4.2. I'll try files for 6.4.*

Hello Glafkon ,  efremovgv . Would you mind trying to patch and report back CPU usage?

CPU usage is fine, thanks for the patch

I did miss an important statement. Appart from:

/usr/share/zabbix/zabbix.php
/usr/share/zabbix/index.php

There also must be autoload.php placed:

/usr/share/zabbix/autoload.php

This will do the optimal loading. Take a screenshot of CPU usage. Then install this file. Have a look of CPU usage again for "php-fpm" process.

Aigars Kadikis Hello. This version autoload.php (which you attached) file compatibility with Zabbix 6.4.3 version?

Yes it is compatible with version 6.4.3

Unfortunately, the problem persists. When opening 6-8 graphs (in different browser tabs) in 1 day (last 1 day), the load on the CPU increases dramatically.
Zabbix version 6.4.5. Ubuntu 22.04.3 LTS. PHP-FPM 8.2. PostgreSQL 15.

UPD.
Slightly reduced the number of graphs in the Templates. Reduced the value of "Max number of columns and rows in overview tables" and "Max count of elements to show inside table cell" from 50 to 30