Suite à la discussion https://forums.fedora-fr.org/viewtopic.php?id=72839 je me suis intéressé au service tuned qui est censé optimiser les performances du système.

Sans avoir fait de bench et en laissant faire "tuned", je constate une meilleure réactivité de mon système quand le profile "balanced" est activé. Il en est de même dans une machine virtualbox quand cette fois le profile "virtual-guest" est activé.
Description  : The tuned package contains a daemon that tunes system settings
             : dynamically. It does so by monitoring the usage of several system
             : components periodically. Based on that information components
             : will then be put into lower or higher power saving modes to adapt
             : to the current usage. Currently only ethernet network and ATA
             : harddisk devices are implemented.
Pour installer tuned: 
$ sudo dnf install tuned
Pour activer tuned au démarrage: 
$ sudo systemctl enable tuned
Pour démarrer tuned si il n'était pas activé au démarrage 
$ sudo systemctl start tuned
L'utilitaire en ligne de commande tuned-adm qui est installé en même temps que tuned permet de voir le profile actif, les profiles disponibles et de changer de profile: 
$ tuned-adm active
Current active profile: balanced
$ tuned-adm list
Available profiles:
- accelerator-performance     - Throughput performance based tuning with disabled higher latency STOP states
- balanced                    - General non-specialized tuned profile
- desktop                     - Optimize for the desktop use-case
- hpc-compute                 - Optimize for HPC compute workloads
- intel-sst                   - Configure for Intel Speed Select Base Frequency
- latency-performance         - Optimize for deterministic performance at the cost of increased power consumption
- network-latency             - Optimize for deterministic performance at the cost of increased power consumption, focused on low latency network performance
- network-throughput          - Optimize for streaming network throughput, generally only necessary on older CPUs or 40G+ networks
- optimize-serial-console     - Optimize for serial console use.
- powersave                   - Optimize for low power consumption
- throughput-performance      - Broadly applicable tuning that provides excellent performance across a variety of common server workloads
- virtual-guest               - Optimize for running inside a virtual guest
- virtual-host                - Optimize for running KVM guests
Current active profile: balanced
Et bien sûr: 
$ man tuned-adm
Il existe deux autres outils graphiques qu'il est possible d'installer pour gérer tuned qui sont tuned-gtk et tuned-switcher.

Hope this help !
un mois plus tard
Alors que tuned démarrait automatiquement au boot de Fedora 34, il ne démarre plus automatiquement au boot de Fedora 35 et je dois le démarrer par "systemctl start".

J'ai fait bien sûr un "systemctl enable tuned" mais cela ne change rien.

Any help ?
$ sudo tuned-adm active
Cannot talk to TuneD daemon via DBus. Is TuneD daemon running?
It seems that tuned daemon is not running, preset profile is not activated.
Preset profile: balanced
$ sudo systemctl status tuned
○ tuned.service - Dynamic System Tuning Daemon
     Loaded: loaded (/usr/lib/systemd/system/tuned.service; enabled; vendor pre>
     Active: inactive (dead)
       Docs: man:tuned(8)
             man:tuned.conf(5)
             man:tuned-adm(8)
$ sudo systemctl start tuned
$ sudo systemctl status tuned
● tuned.service - Dynamic System Tuning Daemon
     Loaded: loaded (/usr/lib/systemd/system/tuned.service; enabled; vendor pre>
     Active: active (running) since Sun 2021-10-31 12:13:41 CET; 4s ago
       Docs: man:tuned(8)
             man:tuned.conf(5)
             man:tuned-adm(8)
   Main PID: 7060 (tuned)
      Tasks: 4 (limit: 38352)
     Memory: 15.8M
        CPU: 666ms
     CGroup: /system.slice/tuned.service
             └─7060 /usr/bin/python3 -Es /usr/sbin/tuned -l -P

oct. 31 12:13:40 lx-desktop systemd[1]: Starting Dynamic System Tuning Daemon...
oct. 31 12:13:41 lx-desktop systemd[1]: Started Dynamic System Tuning Daemon.
$ sudo tuned-adm active
Current active profile: balanced

$ ll /usr/lib/systemd/system/tuned.service
-rw-r--r--. 1 root root 376 21 juil. 20:41 /usr/lib/systemd/system/tuned.service
$ cat /usr/lib/systemd/system/tuned.service
[Unit]
Description=Dynamic System Tuning Daemon
After=systemd-sysctl.service network.target dbus.service
Requires=dbus.service polkit.service
Conflicts=cpupower.service
Documentation=man:tuned(8) man:tuned.conf(5) man:tuned-adm(8)

[Service]
Type=dbus
PIDFile=/run/tuned/tuned.pid
BusName=com.redhat.tuned
ExecStart=/usr/sbin/tuned -l -P

[Install]
WantedBy=multi-user.target
5 jours plus tard
Je me pose la question de savoir si sous Fedora Linux 35 le nouveau service power-profiles-daemon et tuned peuvent tourner en même temps ?
didierg wrote:Je me pose la question de savoir si sous Fedora Linux 35 le nouveau service power-profiles-daemon et tuned peuvent tourner en même temps ?
Bonne question;-). Je viens de désactiver "power-profiles-daemon" et maintenant, "tuned" démarre automatiquement. 
# systemctl stop power-profiles-daemon
# systemctl disable power-profiles-daemon
# systemctl start tuned
# systemctl enable tuned
reboot
après le redémarrage, j'obtiens bien: 
$ tuned-adm active
Current active profile: balanced
$
Merci didierg:pint:.
a+
pll
10 mois plus tard