CFQbyDefault

Summary

Enable Completely Fair Queuing (CFQ) as the default scheduler for Eft and beyond for Desktop Kernels only.

Rationale

In Dapper and previous releases, there has been no default scheduler set at install time, thus the system defaults to the native Linux scheduler. A number of users (including this spec's author) have encountered temporary system lockups when entering Gnome(/KDE/other wm) due to the system load. Enabling CFQ as the default scheduler fixes these lockups. Other major distributions, like Red Hat, also enable CFQ by default.

In Ubuntu today, CFQ can enabled via a bootloader. In grub this is done by either appending

elevator=CFQ 

after the kernel parameter such as

kernel          /vmlinuz-2.6.15-25-686 root=/dev/sdb6 ro quiet splash elevator=cfq 

or by enabling it as a default in GRUB

# defoptions=ro quiet splash elevator=cfq 

(The spec author has written a How-to for this.)

Use cases

These use cases represent actual problems the spec author has troubleshooted for Ubuntu users. These are the negative cases which would be resolved by implementing this spec.

Scope

This specification is meant for Eft and future releases. It is meant for K/E/X/Ubuntu Desktop Kernels but NOT server where deadline would be more appropriate.

Design

This spec proposes that the CFQ scheduler be the default in the desktop kernel.

Unresolved issues

BoF agenda and discussion

To be scheduled

Comments

Changelog


CategorySpec

CFQbyDefault (last edited 2008-08-06 16:41:22 by localhost)