ksmtuned: command not found

Maybe Your $PATH variable doesn't contain the default paths? echo $PATH should give something like:

[root@server ~]# echo $PATH
/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin:/root/bin

If it's empty, You may set the PATH variable with this command

export PATH="/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin:/root/bin"

On CentOS possible default full paths are:

/usr/sbin/ksmtuned - from package: qemu-kvm

You may install the required package with command yum install {package}

Error in other languages:
ksmtuned: bevel nie gevind nie
ksmtuned: comandă negăsită
ksmtuned: comando não encontrado
ksmtuned: commande introuvable
ksmtuned: command not found
ksmtuned: käsku ei ole
ksmtuned: không tìm thấy lệnh
ksmtuned: komanda nerasta
ksmtuned: Kommando nicht gefunden.
ksmtuned: kommandot finns inte
ksmtuned: komut yok
ksmtuned: nie znaleziono polecenia
ksmtuned: níor aimsíodh an t-ordú
ksmtuned: no se encontró la orden
ksmtuned: no s'ha trobat l'ordre
ksmtuned: opdracht niet gevonden
ksmtuned: parancs nem található
ksmtuned: perintah tidak ditemukan
ksmtuned: príkaz nenájdený
ksmtuned: příkaz nenalezen
ksmtuned: команда не найдена
ksmtuned: командата не е открита
ksmtuned: 命令找不到
ksmtuned: コマンドが見つかりません