[Solved] Desktop or server kernel

[eldiener]

What is the difference between the desktop and server kernel for any given kernel release ?

I am running Mageia 4 on my desktop and the default boot item, which is for /boot/vmlinuz, does point to the latest desktop kernel. If I am using only the desktop kernel do I need to have any of the server kernels ?

[doktor5000]

The server kernel is installed by default for systems which have more then 4GB of RAM, multiple processors, or for certain case types.
You don't need the server kernel usually.

For the differences in configuration, take a look:

[doktor5000@Mageia4 ~]$ urpmq -i kernel-desktop-3.12.18-1.mga4-1-1.mga4
Name : kernel-desktop-3.12.18-1.mga4
Version : 1
Release : 1.mga4
Group : System/Kernel and hardware
Size : 49333183 Architecture: x86_64
Source RPM : kernel-3.12.18-1.mga4.src.rpm
URL : http://www.kernel.org
Summary : Linux Kernel for desktop use with x86_64
Description :
The kernel package contains the Linux kernel (vmlinuz), the core of your
Mageia operating system. The kernel handles the basic functions
of the operating system: memory allocation, process allocation, device
input and output, etc. This kernel is compiled for desktop use, single or
multiple x86_64 processor(s)/core(s), using HZ_1000, voluntary preempt,
CFS cpu scheduler and cfq i/o scheduler.

This kernel relies on in-kernel smp alternatives to switch between up & smp
mode depending on detected hardware. To force the kernel to boot in single
processor mode, use the "nosmp" boot parameter.

[doktor5000@Mageia4 ~]$ urpmq -i kernel-server-3.12.18-1.mga4-1-1.mga4
Name : kernel-server-3.12.18-1.mga4
Version : 1
Release : 1.mga4
Group : System/Kernel and hardware
Size : 50768338 Architecture: x86_64
Source RPM : kernel-3.12.18-1.mga4.src.rpm
URL : http://www.kernel.org
Summary : Linux Kernel for server use with x86_64
Description :
The kernel package contains the Linux kernel (vmlinuz), the core of your
Mageia operating system. The kernel handles the basic functions
of the operating system: memory allocation, process allocation, device
input and output, etc. This kernel is compiled for server use, single or
multiple x86_64 processor(s)/core(s), using no preempt, HZ_100,
CFS cpu scheduler and cfq i/o scheduler.

This kernel relies on in-kernel smp alternatives to switch between up & smp
mode depending on detected hardware. To force the kernel to boot in single
processor mode, use the "nosmp" boot parameter.

[eldiener]

The only difference that I see in the descriptions for the kernel are that the desktop kernel uses "voluntary preempt" and the server kernel uses no preempt. Any idea how this translates to one kernel being for a desktop system and another kernel being for a server system ?

[doktor5000]

Check http://stackoverflow.com/questions/8170 ... t-good-for
It's set to voluntary preempt for the desktop kernel to make it feel more snappy, as users have a different expectation on response times for their desktops then servers.

The other difference is the HZ value - higher value also means less response times and allows for more interrupts per second.
For that you may want to check e.g. http://www.advenage.com/topics/linux-ti ... quency.php