Performance

this module use apm-agent-php it enables the site to trace the execution of operations , sending performance m

This module provides a GUI to manually generate entity cache for selected entity types.

This module aims to preserve server resources (processors, memory, thus electricity) by not running the cron on websites that are not used.

DeferJs module is based on a tiny library deferjs.

Insta Queue provides real-time queue processing for Drupal without waiting for cron runs. It works seamlessly with both Drupal core and third-party module queues.

Adds to HTTP headers of a response the performance data of the request not only
as the actual execution time in seconds (rtime), but also the utime and
stime:

• rtime represents the total duration of the response generation process.

• utime represents the actual CPU time, exclusively spent on processing only
  the PHP code of the current request, excluding other background processes.

• stime represents the CPU time spent on kernel processes like disk read/writes
  and other IO operations.

More information: https://www.baeldung.com/linux/total-process-cpu-usage#2-the-cpu-usage

Additionally, it shows the memory usage and the disk read (inblock) and write (oublock) operations.

An example of the HTTP headers output of a response: